Cant create prefix plan for trunk when trunk is ISDN

[DS_Eire]

Hi,

I have the following trunk and network parameters on my OXE

Network Routing Table has - Protocol Type + ABC_F

Trunk Type is:
Trunk Group Type + T2
T2 Specification + SIP
Q931 Signal variant + ISDN all countries

My trunk type was previously set with "Q931 Signal variant + ABC-F", when it was I was able to go into Translator --> Prefix Plan and create a prefix using this trunk ( Node Number/ABC-F Trunk Group )

I then had to change the "Q931 Signal variant+ ISDN all countries" but after I did I was no longer able to create a prefix plan to use this trunk.

It works when the trunk value for Q931 Signal variant is ABC-F but not ISDN all countries.

Is there something i can do to allow me create a prefix for this trunk but still allow the trunk be set to ISDN all countries

Thanks