Spectralink 7642 on OXE system

[vipe]

Hi to everyone.
A customer wish to use a spectralink 7642 dect, in my lab I tested it correctly on a OXO R10.3.
I tried to register it on the IBS system of a OXE R12.4 as a GAP HANDSET.
The subscrition finish correctly with the ring of the DECT. The DECT can call the other users but it doesn't receive.
In the menù "user/go down /DECT set" it appears all normally exept :

Gap display used + False
GAP with display + Without display

This is the result of the dectobs tool:

269 --> STARTING THIS HANDSET OBSERVATION !!!!

269 <-- PAGING ATTEMPT NUMBER : 6

269 <-- PAGING ATTEMPT NUMBER : 5

269 <-- PAGING ATTEMPT NUMBER : 4

269 <-- PAGING ATTEMPT NUMBER : 3

269 <-- PAGING ATTEMPT NUMBER : 2

269 <-- PAGING ATTEMPT NUMBER : 1

269 --- PAGING FAILURE

I tried to increase the "Max numb.of paging retransm" in the DECT parameter with no result.
Any idea ?
Thank you for your support