External number assignment - vendor replication

Hi,

I am trying to maitain an external number range for the vendor replication. but the problem is that the number range that i want to set up as external overlaps with the standard number range in BUCF. The current number range 01 is already in use ( i know that i cannot change it now) . Is it safe to go ahead and delete all BP nos and then change the interval 01 according to my requirements ?. Is there any other way that i can set up the AB number ranges with out having to delete the already generated BPs.We dont want to go with the internal number assignment.did anyone out there ran in to this kind of scenario.

Thanks in Advance

Krishna