update refactoring - where clause substitution

I have to prepare a refactoring which updates a all records with some defined value of type timestamp to a new value.
update test_table set test_column=‘01.01.2999’ where test_column='01.01.1999’

Set clause is controlled by refactoring’s ‘column’ element and I can put the date in a vendor independent format (like “YYYY-MM-DDThh:mm:ss”). But in where clause I should provide the exact string.
Would be nice to have something like:

<changeSet author=“liquibase-docs” id=“update-example”> 

<update catalogName=“cat” schemaName=“public” tableName=“person”>

<column name=“test_time” type=“timestamp” valueDate=“2999-01-01T00:00:00”/>

<test_time type=“timestamp”>1999-01-01T00:00:00</test_time>



That would be a good feature. I logged it at https://liquibase.jira.com/browse/CORE-1593 to track.