ESS Workflow related

HI ESS/Workflow Experts,

We have created some users as Dialog Users and Some as Service Users (only for ESS).

We have maintained Approvers details for different applications in R/3.

If 2nd level Approver or above 2nd level approver is Service User... then Workflow is not going properly to him/her.

Other issue if we are creating Dialog Users if user has not logged in to R/3 but logging to ESS directly then after logging into ESS .. when employee selects ESS then screen display username and password to enter again..

This Should not be the process..

Kindly Suggest Solutions..

Thanks

Puneet