Nokia :: E52 SIP / Internet Tel Functioality

I use an E71 as a SIP client to an Avaya PBX, and all works great.I have tried with an E52 and it will not register and the reason I think is random characters in the REGISTER Contact field:
(In RED)
The PBX returns a Bad request message.
92031914mS SIP Reg/Opt Rx: phone
REGISTER sip:192.168.42.50 SIP/2.0
Via: SIP/2.0/UDP 192.168.42.81:5060;branch=z9hG4bK3h8j4oi8ghhc7nt08ksrq52;rport
From: <sip:804@192.168.42.50>;tag=qma34onsu9hc6ias8ksr
To: <sip:804@192.168.42.50>
Contact: <sip:2XB5Zxan2ZX144ckHIIW@192.168.42.81>;expires=3600
CSeq: 23980 REGISTER
Call-ID: Hq0OoFgvoIfOCAkV-706dKOWSmpRVt
User-Agent: Nokia RM-469 021.013
Max-Forwards: 70
Content-Length: 0
92031915mS SIP Reg/Opt Tx: phone
SIP/2.0 400 Bad Request
Via: SIP/2.0/UDP 192.168.42.81:5060;branch=z9hG4bK3h8j4oi8ghhc7nt08ksrq52;rport

From: <sip:804@192.168.42.50>;tag=qma34onsu9hc6ias8ksr
To: <sip:804@192.168.42.50>;tag=fc3d5e5827c4bde3
Call-ID: Hq0OoFgvoIfOCAkV-706dKOWSmpRVt
CSeq: 23980 REGISTER
User-Agent: IP Office 6.0 (11028)
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, INFO, SUBSCRIBE, REGISTER, PUBLISH
Supported: timer
Content-Length: 0

The E71 sends this correctly.I had to download SIP_VoIP_3_x_Settings_v2_0_en.sis to get it to work as well and this seemd to intall OK.In fact all looks good to go apart from the REGISTER