Transferring Blackberry from another network to VM

[FF99]

I have read lots about this but cannot reconcile the theory with the reality.

I have a fairly basic Blackberry (8520) which was "registered" on a different network some time ago. I believe it was Orange but am not 100% sure.

I have a new Virgin contract SIM with BB service supposedly enabled. When I put it into the phone I do not seem able to get it to "register" for BIS.

I have tried texting "yes" to 789333, as recommended elsewhere, but get an error message.

I have tried to get the "Host Routing Table" sent, but nothing happens.

Orange say it is nothing to do with them and do not understand what I am talking about when I talk about having the BB "de-registered" from the BB network so I can re-register it, and Virgin likewise seem unable to grasp what I am talking about when I call.

Even the idea of a BB 'pin' is not understood when I call.

I am stumped as to where to go next ..... Any thoughts gratefully received.

[raefil]

I went from virgin to Giff Gaff with an 8520 and it did all very easily, I had to do nothing.