ESS testing -> JCO Setups force access to only 1 client?

Hi ... did anyone solve this issue with setup of ESS?

We have J2EE Standalone with portal, XSS and ESS business package.

The ESS WebDynpros on this system require JCO setups (e.g. SAP_R3_HumanResources) to the ERP6 backend.

The issue is that users want to test in different backend clients. However, the JCO setups seem to map this portal to one and only one client.

Anyone have a workaround to this problem?

TIA!

Bart