The frequencies will be different for every area. If you try scanning for channels then you might be lucky and pick up a few VOD streams.... they'll have weird channel names such as "Enx SID7x63", etc. You wont get an EPG for the channels and if nothing is being shown on them then it will just say "channel not available". But they do work.
Best thing to do is get a PCI DVB-C card for your PC and scan the network, as it picks up literally everything; and you can then write those frequencies into your service file on the DBOX.
Liam. EDIT: Just seen that you own a dbox1... i dont know much about these boxes as im not familiar with the DVB2000 software, so this method might not work for you unfortunately. DBOX2/Dreambox is the way forward.