Workflow does not show actual error in the 'Error Message' Process Property

Hi,

We have a workflow deployed as webservice. When there is any error at any step, it always throws error "SBL-BPR-00162: Error invoking service '<?>', method '<?>' at step '<?>'". To see the actual error, we need to look at the logs. why does this this happen in workflow only?

When I try the same step in the BS Simulator, it shows the actual error.

For e.g. EAI Siebel Adapter Upsert method..it shows above generic error if any of the rules violated like userKey. The same data set when run thru workflow, it shows above generic error.