i have info with the next firmware (which seems coming out soon) 3 dlinks should be supported, i am not sure if will be bug so don't take my word, it just if you have any don't throw it away to test

D-Link DWM152 Y
D-Link DWM156 A2 C
D-Link DWM156 A3 Y

Can anyone help me to get this setup.

I've bought a Huawei E173. Works on a PC with Vodafone fine, just sits as idle.

Are there any logs I can use?

there is a new firmware 1.2.1 to try (use the *rst* file)
http://www.draytek.co.uk/support/downloads
for the logs you can see them at Diagnostics > Web Syslog on top of the page are different options

You may need to enable at Network > WAN > USB
If you need to set it via DHCP you need go at Wan>Lan>ehternet
Also check at wan>failover