Hi svakula,
If your API call isn't working...try this:
On Error Resume Next
yourcombobox.Text = yourstring
On Error Goto 0
If yourcombobox.Text = yourstring Then
' we found it - do something
Else
' we didn't find it - do something
EndIf
It's almost as fast as the API call and you still have control over the "not found" condition.
Good Luck,