Help in SLA End Time Determination and Use of CRM_ORDER_MAINTAIN

Hi All Solution Manager Experts and CRM Experts,

We are implementing Service Desk Management for our client through SOLMAN.Based on the priority of the ticket or Service Message created(basically the SLA) we have to show the End Time and End Date on the CRMD_ORDER screen. Now we are using the FM 'END_TIME_DETERMINE' to determine the SLA end time. But we are are not able to get the right time. Though the factory hours are 8 to 5 still whole 24 hours are considered in determing the SLA.Has anyone done something like this. I believe this would have been done many a times, so need guidance. Also please giude on how to use the FM CRM_ORDER_MAINTAIN to show the time on the screen.I mean I have calculated the end time and want to showon the screen with the help of this FM but don't know how to use this.

Thanks In advance,

Saket.