I normally use the following technique to make a remote function call from different schema's dynamically, in a regular PL/SQL block.
column right_instance new_value remtinst
select DECODE(&1,1,'first_schema',2,'second_schema','default_schema') right_instance from dual;
error_code := main_remote_call@&remtinst(param1,param2...);
The same function is defined in all schemas. The choice is dynamically done base on the parameter passed.
But this techniques doesn't seem to work inside PL/SQL block of a form trigger inside Oracle Form.
Could someone please help?