I have an HTC Amaze that the HTC site lists as being on the same frequwencies as the XT network. Unfortunately this (4G) phone was not officially released in New Zealand but in general works as it should with the exception of sending/receining MMS messages.

I have now loaded the APNs as listed for the HTC Sensation as that appears to be the closest to the Amaze
  TelecomDefault or TelecomContent

   APN is set to wap.telecom.co.nz

   Proxy is not set

   Port is not set

   Username is not set

   Password is not set

   Server is not set

   MMSC is not set

   MMS Proxy is not set

  MMSPortis not set

   MMS Protocol is set to WAP 2.0

   MCC is set to 530

   MNC is set 05

   Authentication Type is not set

   APN Type is set to default,hipri

   TelecomDefault is marked with a green dot

 

  TelecomData or TelecomInterent

   APN is set to internet.telecom.co.nz

   Proxy is not set

   Port is not set

   Username is not set

   Password is not set

   Server is not set

   MMSC is not set

   MMS Proxy is not set

  MMSPortis not set

   MMS Protocol is set to WAP 2.0

   MCC is set to 530

   MNC is set 05

   Authentication Type is not set

   APN Type is not set

 

  TelecomMMS

   APN is set to wap.telecom.co.nz

   Proxy is not set

   Port is not set

   Username is not set

   Password is not set

   Server is not set

   MMSC is set to http://lsmmsc.xtra.co.nz

   MMS Proxy is set to 210.55.11.73

  MMSPortis set to 8080

   MMS Protocol is set to WAP 2.0

   MCC is set to 530

   MNC is set 05

   Authentication Type is not set

   APN Type is set to MMS

 Still no joy with MMS and after an approach to HTC they tell me the AMAZE is not compatible with XT frequencies!.

Am I missing something here as the specs listed on their site and those for XT seem the same..UMTS850/2100. I'd really like to get the MMS feature working as the phone is a great phone - so much so that I'll keep it even without MMS