From a suggestion per Jim Kinneman:
Erp.Contracts.EngWorkBenchSvcContract **engWorkBench** = Ice.Assemblies.ServiceRenderer.GetService<Erp.Contracts.EngWorkBenchSvcContract>(this.Db, true);
Erp.Contracts.EngWorkBenchSvcContract **engWorkBenchCheckIn** = Ice.Assemblies.ServiceRenderer.GetService<Erp.Contracts.EngWorkBenchSvcContract>(this.Db, true);
I defined a different service to execute the CheckIn method. Worked great.
Thanks, Jim!
Joe