Philipp_Thomsen,
If you are after the .tga files for the picture which sits just above the radio/radar operator it is "druck_radio_x.tga" where x= the sub type (eg 7, 9, 21 etc) you are interested in.
I have a collection of images which I use with the SH3 Commander Random folders to mix them up each time I set sail. Within the SH3 Commander construct, they reside in the Data\Textures\TNormal\Tex directory, and hence, are copied to the same place in the main SH3 directory. No need to play with any .dat files
Works fine on my install (GWX 2.0 + SH3 Com 2.7 etc) so hope this helps.
Cheers