I should of guessed that was your problem last night and not the .shader file
TGA files are used when texture compress is off. With texture compress on it uses .dds files.( .dds is a Direct 3D file format )
You'll have to open the .dds file and edit it for your changes to show up. This is a common problem overlooked in most of the tutorials.
You can get the required .dds plugins here
For Adobe PhotoShop
Save to your plugin directoryYou may also need this
Put these dlls in windows\system For Paint Shop Pro:
First thing you must do is to setup PSP (Paint Shop Pro) with the DDS plugin. To do this find out where your PSP 7 is installed
(normally "C:\Program Files\Jasc Software Inc\Paint Shop Pro 7") in explorer.
Once you have you will need to look for a directory called something like "Plugin",
if the directory does not exist then simply create the directory called "Plugin".
Then go inside the directory and place the unzipped file in the DDS Plugin into that directory.
This is the same dds file used for Photoshop.
Now open PSP and goto File--> Prefrences --> File Locations
and choose the plu-in filters tab. Use browse to find the "Plugin" directory you made and hit ok.
Let me know if you need more help.