Acumatica - computing field default value -

in acumatica want compute "quote expires" date on sales order entry form based on date new order of type "qt" created. date computed adding default "default quote expiry days" set in sales order preferences. example if default expiry days = 45 (setup) , order created on april 1, 2015 default date "quote expires" on sales order entry form may 16, 2015 (april 1, 2015 plus 45 days). expiry date may overridden user.

any examples appreciated.

protected virtual void soorder_usrexpireddate_fielddefaulting(pxcache sender, pxfielddefaultingeventargs e)     {         soorder row = e.row soorder;         if (row.orderdate.hasvalue)         {             e.newvalue = row.orderdate.value.adddays(45);         }     } 

for example added custom field soorder called usrexpireddate, feel free replace number 45 kind of setup.