Legacy API (v4) in Sugar 13

I'm trying to leverage an old v4 API in Sugar 13. It can not be re-writen to v11 as there are a few hundred existing external clients using the OLD API. I need to find a way to make it work. When you access the v4 API I receive this message

 PHP Fatal error:  Uncaught Error: Object of class SugarWebServiceUtilv4 could not be converted to string

Thoughts? The issue is with a ReflectionClass