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A few days ago, I had posted a tutorial from the XDA Developers forum on How to Install, Setup, Configure & Provision the inbuilt VoIP SIP client on Windows Mobile 6.0. The only caveat to the solution was that you needed to manually create the _setup.xml configuration file and make a CAB file out of it so that Voip could be configured on the mobile device.

Shaun33 from the XDA Developers forum left a comment on the previous post stating that he has created a freeware utility called SIp Config Loader that will create and load the _setup.xml file directly on the Windows Mobile 6 device for you automatically. You just need to enter your SIP based VoIP provider’s details from the GUI of the application such as SIP Server Name, Port Number, Username and Password.

This is only the initial release. Future versions will support:

Saving of Config Files
Switching Config Files
Exporting File (without username & password)
Importing Files (with username password)

Download here

Update: A new version that supports Enabling & Disabling of VoIP SIP over 3G/GSM is available. Download here