The UID_CONTROL command toggles the server UID. For this command to parse correctly, the UID_CONTROL command must appear within a SERVER_INFO command block, and SERVER_INFO MODE must be set to write.
Example:
<RIBCL VERSION="2.0">
<LOGIN USER_LOGIN="adminname" PASSWORD="password">
<SERVER_INFO MODE="write">
<UID_CONTROL UID="Yes"/>
</SERVER_INFO>
</LOGIN>
</RIBCL>