unlang & expr

Hi, I need do some arithmetic operation in the soh-server, so I tried use the expr module. example: server soh-server { ...     update control {          &Tmp-Integer-1 := %{expr: 1 + 2 + 3}     } But from syntax checker I received error message: "Syntax error: Expected comma after '%{expr:': 1 + 2 + 3}" Is possible use expr in this case? Petr Linke