One or more application server components serve to associate one or more digit strings with one or more numbers available to one party of one or more parties to a call and to impose one or more charges on the one or more numbers available to the one party to the call. Where the one party to the call employs an equipment that fails to support a P-Asserted-Identity header of the call, one application server component of the one or more application server components serves to: remove from the header of the call one digit string of the one or more digit strings available to the one party; insert into the P-Asserted-Identity header one number of the one or more numbers available to the one party associated with the one digit string; and to impose one charge of the one or more charges on the one number associated with the one digit string.