APEX

I want to be able to execute procedures on remote databases. I do this after some lov's and text feilds have been entered and the submit button is clicked(this is a page process running PL/SQL anonymous block). Problem is the name of the procedure is dependant on the name of the database selected. For example this works:

dba_audit_pkg.create_user@remoteDB(
pi_username => :USERID
,pi_type => 'SUPPORT'
,pi_dbname => 'IB');

but this does not:

dba_audit_pkg.create_user@:P1_DATABASE(
pi_username => :USERID
,pi_type => 'SUPPORT'
,pi_dbname => 'IB');

Does anyone know how I can generate the name of a procedure depending on a variable ?

Thanks
Steve