I haven’t worked with the Bank stuff. However, I would first ensure the Erp.Contracts.BO.BankFundTran assembly is added to your list of references. That’s typically the cause of “The type or namespace name does not exist” error.
Click the Usings & References… button at the bottom-right and add the Erp.Contracts.BO.BankFundTran assembly.
It’s easy You reference incorrect assembly. You have to use Erp.Contracts.Proc.BankFundPost instead of Erp.Contracts.BO.BankFundTran. Current one defines BankFundTranSvcContract, not BankFundPostSvcContract.
ERP contains a huge number of libraries. Since BPM needs to show only server-side assembly it has to scan related catalogs on the server and send the result back to the client. Originally we did it in one batch, but the first call looked as the system hang. Further calls use client-side cache which lives until epicor.exe restarted. To improve the user experience we switched to page-based load. It allows (at least) to get some of the results pretty fast.