Also, I use gimp. When I go to save as dds, which one of the format options should I choose? Because I can't find a dxtn5 argb 8bp with interpolated alpha in the selection.
take a look at http://code.google.com/p/gimp-dds/#Screenshots ...
- for the cl and the da : bc3/dxt5, generate mipmap, use dithering, Mipmap filter Lanczos
- for the nm, copy the red channel to the alpha channel and save like a cl map... or use the dxtn format
Your nm map is only a bump map... instal the gimp normal map plug-in found at http://code.google.com/p/gimp-normalmap/ ... will help you to create the better quality blueish normal map...
need your .mesh, so i can test it ingame with you textures...
as for hardpoint, i place them on my wings3d scaled model...

The selected hardpoint is the red one and his position is the value of the reference point... for direction matrix, i have a table for the major direction left/right/front/back... i use notepad for add them to the .mesh... plan is to create in the future ( when i have a lot of time ) a wings3d plug-in able to export directly to .mesh without using xsi who hate me... if i have more free time, make a plug-in who make the reverse...
But as now, if you have problem with hardpoint, go to http://soase.weebly.com/xsi-add-ons.html ... scroll down to the "meshpoint" section.... there, you will find a very useful plug-in for xsi who create sins hardpoint with control about the game hardcoded limit...
Now that i think, a other useful plug-in for gimp at http://tml.pp.fi/gimp/pspi.html ... PSPI is a little plug-in who allow to run photoshop plug-in in gimp...