incompatibility issue with dexim a/v dock

[cjwj]

I have tried 2 different Dexim DRA017 a/v out dock from O2 in the UK, and while they charged the phone, and allowed the remote to alter the volume, neither sent a/v info to my tv via composite audioL/audioR/video cable. And I tried changing over red phono with yellow phono. I also received incompatible with 3G iphone message and freezing when my iphone (which is jailbroken) was in the dock, but not connected to a tv.
I have emaiedl Dexim and was assured that there was full compatibility.
Has anyone else experienced this and has it got anything to do with jailbreak issues?
cjwj

 

[cjwj]

Maybe it's a general problem ie you have to use an apple av cable to connect the dock to the tv. I've noticed a lot of posts on that subject. Dexim say that it will work with just a standard av 3.5mm 4 terminal jack to 3 x phonos.
Has no one else bought one of these?
cjwj