Fritz!Box 3270 v3 international - fritz!os 05.2x possible in freetz trunk??

Hi,
I have a one question:
I any possibility for enable fritz!os 05.2x in newest trunk version of freetz for 3270 v3 international version?
I have on my hard drive the older image 96.05.23 for this box, but I can't change the os version in config menu of freetz.
For 7270 models there is no problem with that, but for 3270 only 05.5x Fritz!os version is possible to mark.
I nedd an older fritz!os, because this 3270 will work as wifi repeater for my 7570 vdsl model, which works on older os as 05.5x (which have new version of wds system, no compatible with older versions). On my 7570 I can't put in an alien version of 7270 firmware, because I'll lost VDSL (my internet connection) support.

Regards

Problem solved.
Solution:
1. add line to the section 'config FREETZ_AVM_HAS_FIRMWARE_05_2X'
( FREETZ_TYPE_3270 && !FREETZ_TYPE_LANG_IT ) || \
of the ./trunk/config/avm/availability.in file
2. make oldmenuconfig
3. make menuconfig
4. copy file
FRITZ.Box_WLAN_3270_v3.en-de-es-it-fr.96.05.23.image
to the ./trunk/dl/fw directory.
5. make

Regards