Packet 8 + Broadvoice + Asterisk

I currently have a Packet 8 line (only provider with local number) I have a data only T1 in the office. I am looking at setting up a * server and want to continue to use the packet 8 number and service. I plan on getting a tdm01b and connecting the packet 8 line to it. I want to add some additional lines, but would like to use broadvoice since they are * friendly. All my customers currently dial the packet 8 # and I want them to continue doing so. If I’m on the Packet8 number I want the call to come through the Broadvoice. My idea is that I can forward the packet 8 # to the broadvoice number and then this will act as a kind of “Roll Over”.

Has anybody done anything like this? Does it sound workable?

In house we will use SIP Phone through ethernet or softphones some places.