Restricting search help of UWL

Hi Experts,

Please provide me solutions for following issues.

EP 7.0, R/3 4.6

1. 'Manage substitution rules' of UWL iview that is available with EP 7.0 is not supporting with r/3 4.6.

Error message is 'system does not support substitution methods'. Is it true? or is it because I am lacking with some configuration?

2. In 'manage substitution rules' i need some restrictions while he search for users to assign as substitute for his tasks.Search should display only users assigned with the same role of the user who is doing the search? Now it is displaying all the users in LDAP.

is it possible to restrict the search of standard iview?

Any comments is highly appreciated.

Regards,

John.