1st. Download img tool from the link here
2. Download the cloth mod
3. Go to San Andreas Directory and then modles. Go to Player.img
4. In the Zip you downloaded there should be a (or more) .txt files. Remember the .txt file name.
5. In image Tool go to edit, find and type the file name in. Once you have it selected delete it. Add the .txt file in the zip. and it should be done!
Just noticed it but shouldnt the files you install for clothes be .txd .....