Purchase Order Required Flag on Service Orders - Is there anything to deal with this

Hello

Just wondering if there is a way in Service order management that tells the users when creating a service order the customer requires a purchase order to be for every service order that will be invoiced to them 

There is a flag in billing infomration in the address book for this however appears to only work for the sales module.

I am aware we can use the credit message flag to assist with the end user knowing there is a message against the customer however can't seem to find anything associated with purchase order required

regards