PROBLEM IN SERVICE P.O

Dear cons

We want to create a service P.O. by activating unlimited service item qty & maintaining overall value limit. When we will create a service entry sheet w.r.t P.O the system will check the value limit. When the value of the entire serv ice entry sheet will same as the over all limit at that time system will not allow to create service entry sheet further. Because it has already reached the overall value limits. if we activate the unlimited qty as well as mainting value limits which is not available in standard system so we want to make some enhancement. Pl. provide me some solution in this regard. Which user exit we will use.

nrk