Where's my IX/2 tower?

[filefool]

At first i must say that my current career is the first one with a IXer, since i always saw the VII as the "real" u-boat. Nevermind

I started in 1939 with a IIA and upgraded to a IXB once i had enough renown. Looking at the equipment chart it said that the IX/2 conning tower will be available in early 1941.

In April 1941 it still wasn't there, so i thought that the IX/2 could only fit on a IXC. Now its August 1941, i upgraded to a IXC and i still can't use the IX/2 tower. The weirdest thing is that my IXC with the IX/1 tower doesn't have the 3,7cm Flak anymore and it can't be equipped via the upgrade screen.

I am using GWX 2.0 and SH3 Commander 3.0

Enhanced Damage effects, no medals on crew and 16km atmosphere mod are enabled.

Can anyone tell me what's going on? I tried to look into the files but i just can't find the file where the availability dates for the conning towers are located.