question about dxt.bmp

Im new to repainting....so just some simple questions so i can complete what im trying to acheive with somewhat limited skills!!
All im after doing is changing the brightness of a blue colour on an aircraft.
Using dxt.bmp, i tested my skills on the default cessna, opening with dxt.bmp, sending to PS, changing some of the colours using the wand thing and basicaly filling in over the old colour with my new colour, opacity around 45% so that panel lines and so on are still visible.
I then saved, reloaded in dxt.bmp and saved into the cessna texture folder, of which i had created a new one. I did all three or four textures like this, alterd the cfg and hey presto! it worked and appeared in fs9.
The aircraft im really wanting this to work on however is a fs2002 aircraft. Im unsure what format i should save my edited .bmps as 32bit made fs9 crash, 24bit made them not show up at all although the aircraft model itself did show!
I guess im doing somthing wrong, and it would be easier to use the paint kit with the fs2004 model but try as i might i just cant seem to get the hang of re-painting from scratch!
All im after doing is changing the brightness of a blue colour on an aircraft.
Using dxt.bmp, i tested my skills on the default cessna, opening with dxt.bmp, sending to PS, changing some of the colours using the wand thing and basicaly filling in over the old colour with my new colour, opacity around 45% so that panel lines and so on are still visible.
I then saved, reloaded in dxt.bmp and saved into the cessna texture folder, of which i had created a new one. I did all three or four textures like this, alterd the cfg and hey presto! it worked and appeared in fs9.
The aircraft im really wanting this to work on however is a fs2002 aircraft. Im unsure what format i should save my edited .bmps as 32bit made fs9 crash, 24bit made them not show up at all although the aircraft model itself did show!
I guess im doing somthing wrong, and it would be easier to use the paint kit with the fs2004 model but try as i might i just cant seem to get the hang of re-painting from scratch!