Synchronization Editor: SAP-Sync-Project - Creating virtual Script Property for the target System side

I tried [1] in the read script - Tab of my virtual attribute. 

If i inspect a userinrole - record in target system browser, i get the error message in [2].

Does that mean that it is impossible to query objects and joined objects in SAP-Target-System?

[1]

Imports VI.Projector.Connection

Dim whereClause As String = String.Format("USERNAME = '{0}'", $UNAME$)

Dim UserObj As ISystemObject = SystemObject.Connection.QueryObject(SystemQuery.From("USER").SelectAll().Filter(whereClause)).Result.FirstOrDefault

 If Not UserObj Is Nothing Then

            Dim bapilogond_class As String = UserObj.GetValue("BAPILOGOND~CLASS").AsString

            Return String.Format("{0}", bapilogond_class)       

End If

[2]

[1777160] Property (vrt_xyz@UserInRole) could not read the value from system object (K211987 - XE_SHK-IP_ANALYST_BAUSP).

[1777208] Error running (vrt_xyz@UserInRole)'s 'Get' script for (K211987 - XE_SHK-IP_ANALYST_BAUSP).

Exception has been thrown by the target of an invocation.

[1777009] Error loading system objects of class USER (all) (USER_Master).

[1777351] The target system and/or the connector does not support system filters. The following filters were passed but cannot be applied.

USERNAME = 'K211987'

You cannot use the QueryObject as there is no system filter support. Correct.