To use peoplepicker-searchadforests with credentials, which you need to specify if you don’t have two-way trusts in place, you must first set an encryption key:

STSADM.exe -o setapppassword –password <encryptionpassword>

Then you need to specify an account for traversing the other domain and the web application that should be able to add users from that domain. You need to set the property for each web application you want to be able to traverse the other domain:

STSADM.exe -o setproperty -pn peoplepicker-searchadforests -pv domain:<domain which will be traversed>,<account with rights for traversing the domain>,<account password> -url <url for the webapp where you want to add users from the other domain – example: http://mywebapp>

Example

STSADM.exe -o setproperty -pn peoplepicker-searchadforests -pv domain:ProActive,ProActive\Abdel-Rahman.Awad,******* -url http://mywebapp