Need correct user exit to modify the code for segment E1EDP01

Dear All,

I have to modify the code for a requirement, if the length of PO's item text exceeds 68 characters, the segment E1EDPT2 will not get created for both ORDERS and ORDCHG message type of a outbound idoc.

For this need, which user exit i am suppose to use. I have tried to debug both the user exit 
EXIT_SAPLEINM_011 and EXIT_SAPLEINM_002, but its not stopping in the breakpoint.

Kindly suggest something.

Thanks.