I can't include a filter to a one-to-one assocation in my .hbm.xml file.

It's working for one-to-many associations:
<bag name="subList" cascade="all,delete-orphan" lazy="false" inverse="true">
<key column="ID"/>
<one-to-many entity-name="TestSubList"/>
<filter name="FILTER" condition=":filterAttr = FILTER"/>
</bag>

<filter-def name="FILTER">
<filter-param name="filterAttr"/>
</filter-def>

... but I can't include a filter to a one-to-one association:
<one-to-one name="oneToOne"
entity-name="TestOneToOne"
cascade="save-update">
<filter name="FILTER" condition=":filterAttr = FILTER"/>
</one-to-one>

--> I get this message: "The content of element type "one-to-one" must match "(meta*,formula*)"."



Is there a workaround for this problem?