Claes beat me to it - but here is what I wrote:
Hi,
A fairly straight forward setup, so I assume your dealer is correct. Please forgive me, but starting from scratch: Each input on your tv can be mapped to a key on the Beo4. In the setup menu of the tv you assign each connection to V.MEM, DTV, V.AUX etc.
If you connect your DVB-C box as V.MEM in the tv's setup menu, you may run into problems using the PUC/STB-C (=set-top-box controller). As the DVB-T uses the DTV-connection, I would recommend using V.AUX on the Beo4 and the V.AUX(STB) in the setup menu on the tv. This will trigger a request for the id of your DVB-C box so that you can control it via the Beo4. I am afraid that you will have to use LIST to gain access to V.AUX, so it looses out on WAF.
I am not sure if, on the BV8, you can use any of the other hard buttons: On the BS3 you can assign a connection as "DVD" and still get access to the PUC/STB-C list.
Being at work I am not able to check this - but I will have a look tonight.
Roger