1. Add the following Object Initialization Rule to your type (wt.part.WTPart)
<!-- set the Boolean IBA -->
<AttrValue id="endItem" algorithm="wt.rule.algorithm.BooleanConstant">
<Arg>true</Arg>
</AttrValue>
<!-- set the String IBA -->
<AttrValue id="source" algorithm="wt.rule.algorithm.StringConstant">
<Arg>buy</Arg>
</AttrValue>
<AttrValue id="partType" algorithm="wt.rule.algorithm.StringConstant">
<Arg>inseparable</Arg>
</AttrValue>
<!-- specify AttrConstraint tag -->
<AttrConstraint id="endItem" algorithm="com.ptc.core.rule.server.impl.GatherAttributeConstraints">
<Value algorithm="com.ptc.core.rule.server.impl.GetServerPreGeneratedValue"/>
</AttrConstraint>
<AttrConstraint id="source" algorithm="com.ptc.core.rule.server.impl.GatherAttributeConstraints">
<Value algorithm="com.ptc.core.rule.server.impl.GetServerPreGeneratedValue"/>
</AttrConstraint>
<AttrConstraint id="partType" algorithm="com.ptc.core.rule.server.impl.GatherAttributeConstraints">
<Value algorithm="com.ptc.core.rule.server.impl.GetServerPreGeneratedValue"/>
</AttrConstraint>
2. Edit the following %WT_HOME%\codebase\com\ptc\core\rule\server\delegate\init\RuleConfigurableTypeAttribute.properties.xconf:
<Property name="wt.part.WTPart" default="number,name,lifeCycle,lifeCycle.id,teamTemplate,teamTemplate.id,folder.id,organization.id,endItem,source,partType"/>
3. Run "xconfmanager -pF" in Windchill Shell and restart Windchill