DXT3

I just got FS2004 and tried a repaint I did for 2002. I noticed the texture were blurred. I loaded the origional texture and it is 8 mips DXT3 format. I then loaded the repainted texture and noticed it is 10 mips 16 bit 565 extended bitmap. This is my first attempt at painting extended bitmaps. My procedure was to open in DXT Bmb with "load extended image". Then I sent it to PSP7 and painted it. Then I saved it to my desktop. I then loaded in DXT Bmp with "load normal image" and saved with "save extended image". How can i convert these textures to DXT 3 format? 
