Problem in BAPI creation

Hi,

I have created a Function Module as Z_DOC_READ as a local Object.

Now , I am trying to make it as RFC enabled. But, It not allowing to do that.

Instead it is throwing one Message as

"GENERIC TYPES ARE NOT ALLOWED IN RFC".

Please let me know, what is the wrong with this?

Any steps to be followed, while Making the FM as RFC enabled?

Please let me know.

Regards

Sandeep