You seem to be getting conflicting sporadic information here and in your other thread, so here's essentially how the process works:
1) Build and texture your ships main hull object (in softimage XSI is it?). For in-game efficiency sake you should aim for a single UV mapped image, but that's not a requirement. Call this object 'detail0'.
2) Model and texture turrets and other subobjects (usually things that rotate in some way like radar dishes) that you need the game to treat as independent from the main hull.
At this point, say you had a two part (base and arm) style turret you wanted to have. Here's what you'd need there:
- A) *REQUIRED* A turret base object with it's centre located at the point you want the whole turret to pivot around. (Call it say; 'Turret01-base')
If it's a topside turret face it forwards, if it's a belly turret face it backwards. (You can now do other orientations but don't worry about them yet)
- B) *REQUIRED* A turret arm object with it's centre located at the pivot point of the arm shape. Ie, in the base somewhere so they look attached. ('Turret01-arm')
Turret arms should always point straight out of the base they're attached to. Also, only have one turret arm object per turret base object. However, since the arm can look like whatever you want, you can model it so there are up to 3 or 4 arms in that one object.
- C) *OPTIONAL* An (empty/helper/whatever XSI calls objects that have no geometry) called 'firepoints#' where # is some number thats only purpose is to prevent any two helpers having the same name. Doesn't matter where this is located, but typically it's placed somewhere in the turret base object for convenience.
- D) *OPTIONAL* Some helper(s) of any name (let's call them "FP01", "FP02" for now) positioned on the firing point(s) of the turret. Ie, if your turret has 2 gun barrels you'd have two of these helpers positioned at the tips of each barrel. These helpers should be orientated so their Z axis is in-line with the barrel arm, as this defines the direction in which the guns firepoints face in relation to the barrels.
- E) *REQUIRED* Now set up the turrets hierarchy like so:
detail0
|
|-Turret01-base (MULTI-PART TURRET, 2 BARRELS)
| |
| |-Turret01-arm
| |-firepoints01
| |
| |-FP01
| |-FP02
|
|-Turret02 (SINGLE PART TURRET, ONE FIREPOINT)
| |
| |-firepoints02
| |
| |-FP03
|
3) Build (or rather poly reduce a copy of the main LOD) up to 4 LODs. Position them in the same location (with the same object centre locations) as detail0 and name them detail1-3. Also make sure these use the same texture as the main LOD unless doing so is really really impossible and you're crazy about getting pretty lods. Do not make these objects children of detail0 or anything.
4) Build debris chunks (I do this by ripping up a copy of detail1 and filling in the holes) and place them in their appropriate locations in relation to the original model. Name them 'debris##' where ## starts at 01.Do not make these objects children of detail0 or anything.
5) If the ship needs a shield, make it out of an untextured, roughly 80 faced sphere object that's been mashed around to fit the ship's shape correctly. Call it "shield".
6) Save as Collada DAE and open it up in the Collada version of PCS2. Save it as a POF somewhere straight away.

7) Now add POF data, still using PCS2. The best place to go to learn about how all the settings work is
Bobboau's PCS1 tutorial. Pretty much everything there still applies to PCS2, though it should be noted that you can now grab and drag your firepoints, subsystem centres etc around by holding ctrl + dragging. Takes a bit of getting used to, but it works pretty well.

The POF data typically entered/edited in a completed ship includes:
Header--> Mass (Automatically done during conversion)
--> Moment of Inertia (Click 'Recalculate' to do that automatically)
Subobjects--> Add subobject properties to each non-LOD and non-Debris object in the model.
For turrets this would be:
$special=subsystem
$fov=180
$name=GunTurret
Where fov is Field Of View cone and name isn't used.
--> Set up rotation Type and Axis for those turrets that do rotate.
Weapon Points--> Gun and missile point banks, locations and normals for fighters and bombers only.
Docking Points--> Set up a name like "$name=main dock"
--> Assign a path that ships use to get to it.
--> Add two dockpoints with the correctly facing normals, and about 1 unit apart to define orientation.
Thrusters--> Set up engine properties to be "$engine_subsystem=$engines" where "$engines" is the name of the ships engine subsystem.
--> Set up individual thruster glow locations, radii and normal orientations.
Glow Points--> Typically only on terran ships, set up the static or blinking points of light that appear on ships hulls.
Special Points--> Set up the default 5 subsystems: $communications, $navigation, $sensors, $weapons, $engines
--> Define properties of "$special=subsystem" for each one.
--> Set up radii and locations for each one.
Turrets--> Should all be done automatically already if you followed the optional steps in 2).
--> If not, set up each turret individually, with:
--> A parent subobject (the base)
--> A physical subobject (the arm)
--> A normal for the whole turret - ie, where the barrels point.
--> Locations for each firing point relative to the turret base.
Paths--> Just be lazy and do this last by clicking Auto Gen.

Look to Bob's guide if you want to know more/fiddle.
Eye points--> Sets up the parent subobject, location and normal direction of where the bridge/cockpit is on each ship.
Shield--> Should be done during conversion. Can't edit it here but you can import shields from other ships.
8) Make a TBM (table) entry for the ship. The wiki should help greatly here:
http://www.hard-light.net/wiki/index.php/Tables9) Test in the ship lab by pressing F3 in the main hall.
Hope this helps.
