Turning Off Autonumbering
Assuming that autonumbering for a specific object type has been set up, you can turn off autonumbering in a specific context by including the following
AttrConstraint tag for the number attribute in the context:
<AttrConstraint id="number"
algorithm="com.ptc.core.rule.server.impl.GatherAttributeConstraints">
</AttrConstraint>
Using this tag, which has no Arg tags specified for the constraints, sets the display field to a text box so that the user can manually enter the number.