USB 3G modem problems

[woody]

I'm trying to install a ZTE MF 691 USB modem (aka T-Mobile Webrocket). I got this working successfully on Windows 7 and on Linux Mint, but I've had no success with getting working with my Pogoplug running Arch Linux Arm. I have usb_modeswitch installed, and it seems to correctly switch the device, but I can't locate a USB port that's associated with the device.

lsusb looks good:
$this->bbcode_second_pass_code('', 'Bus 001 Device 005: ID 19d2:1203 ZTE WCDMA Technologies MSM MF691 [ T-Mobile webConnect Rocket 2.0]')

That's the correct VendorID:ProductID for the device. wvdial config cannot locate a working USB port.

So here are my questions:
1. Has anybody else gotten this or a similar USB modem to work on a Pogoplug?

2. Does anybody know a way to figure out why the device is not getting assigned a USB port or does anybody know a way to force a USB port assignment?

Any thoughts or advice appreciated.