WLan lock up RTL8188SU

I am afraid I am quite new to the DreamBox world and OpenPli in particular although I love OpenPli and I intend to stick with it. I have a DM500HD clone and I am running OpenPLi-2.1-beta-dm500hd-20120530-sim2-ssl84b normally with a LAN connection. Recently I tried to use the WLan via a usb dongle I had lying around. It is a RTL8188SU chipset. The box detected it, it could find the SSID and the gateway, I set up the password correctly, but when it came to activate the link it just locks up. Presumably version 2.1 contains a driver for the RTL8188, otherwise it would not be recognised, but something goes wrong when it comes to connecting the link.
Has anybody else had similar problems. Is there another driver that could be installed?

Thanks in advance