QP_CUSTOM--OE_MSG_PUB

Hi All
QP_CUSTOM is a standard package given by oracle to customize the price derivation based on our custom logic.
Recently i customisee this package to get freight charge based on the wegith of the line items.
This was not so tough to achieve but the user want to show some messages when ever any exception occurs....But the qp_custom is supposed to return a number..
This api is called from dynanic formual on some event like saving entering ..
The solution we thought of is form personalization by returning some constant number an throw exception when we encouter that values...But still i didn't work...the possible ways form personalization works are far less than the ways it didnt work...

after sorm R&D on google and metalink i found that there is api oe_msg_pub to put error messages...
But unfortunately i didnt find right code to use it properly after some hit and try
i figured out that
oe_msg_pub.add_text will add a message
oe_msg_pub.add will put the message on the stack..This will display messages in the
message window in order entry screen
i thought it would be better if we display message in a modal window
so i gave a blind try like define a message in application developer message window


fnd_message.set_name ('XXCUST', 'XX_ERROR_MSG');
fnd_message.set_token ('MESSAGE', 'No Shipping Charges defined');
oe_msg_pub.ADD;
"Message is a token in the message"
This really works...every time you change qp_custom package close the order entry form ,reload it and try..