The directory structure for a JSGME ready IIA skin should be data\Submarine\NSS_Uboat2A and should be in the form of a single file - the NSS_Uboat2A.dat. this contains the skin in the form of an embedded TGA - the typ 2A_Hull.tga. The current GWX NSS_Uboat2A.dat may be different from the one containing Fubar's skin

. If you're familiar with Silent 3ditor & editing dat files, it may be worthwhile extracting the TGA from Fubar's skin dat & importiing it into the GWX typeIIA dat.
If you're not comfortable with editing dat files in this way, then post a download link for your TypeII skin & I'll see what I can do.