has anyone managed to get any non Tosh SIP phones working with a CIX?

i have been trying with a Linksys SPA922 (Sipura) and the xTen softphone without much luck....however I also have a Hitachi WiFi SIP phone which our dealer supplied which works fine ..

transferring the settings that seem relevant over doesnt seem to be working - is there something i may be missing (I'm using the same SIP ext number for my tests as the Hitachi - which is turned off of course)

thx
dave