I've made two, one for the Jyunsen B and one for the Type AM submarine.
I've uploaded them on my main FF page, for those who have my mod and wanna try to get them working
I've changed this in the NSS_Jyunsen_B.upcge :
[UserPlayerUnit 1]
ID=Jyunsen_B
NameDisplayable=Jyunsen B
UnitName= SS-I 25
Type=Jyunsen_B
UpgradeClass=2
UnitInterval= 1941-10-01, 1945-12-31
ExternalClassName=SSJyunsen_B
Nationality=German
CrewRanks=15
Evolution= Normal
Damage= 0
TextureName=data/Submarine/NSS_Jyunsen_B/NSS_Jyunsen_B_T01.tga
LightmapTextureName=NULL; data/Submarine/Nss_Jyunsen_B/NSS_Jyunsen_B_001.tga
NormalmapTextureName=
data/Submarine/Nss_Jyunsen_B/NSS_Jyunsen_B_N01.tga
MenuSilhouetteTextureName= Jyunsen_B_1.tga
MaxPettyOfficers=32 ; max number of crewmembers over rank 4
MaxOfficers=6 ; max number of crewmembers over rank 7
no bump :
bump :
A picture is worth a 1000 words....
so all we have to do is activate the bump map ! good idea Skwasjer !!!
And thanks to Danlisa 
for this superb tutorial, now we see what we missed !!!! 
Keltos