Ahoi @ gcroix
The most important answers can be found here:
http://www.subsim.com/radioroom/showthread.php?t=155786
Important is that you have at least JSGME and the 4GB patch for large modifications installed.
As for the large-mod issue (because of the simple installation), there are probably two options for the Silent Service.
1. FORTSU
http://www.subsim.com/radioroom/showthread.php?t=226270
2. Ralles RealModPack
Just go to my signature
Hope I understood you correctly and this helps you further.
Ahoi Ralle
