<message_body>
<pm:set_cell_param>
<cell_data id="PM">
<param name="OntMax">200</param>
<param name="OntSyn">false</param>
</cell_data>
</pm:set_cell_param>
</message_body>

A setCellParam message is sent by a client application or another cell service to add a cell parameter to the PM cell. The cell needs to exist prior to calling this service. If the cell and parameter name already exist the record will be updated.
The domain, username, and password are sent in the header of the message so it does not need to be sent separately in the <message_body>.