Batch insert using groovy Sql?

Question

How can you do a batch insert using groovy Sql while simulating prepared statements? All the examples I've found are similar to the following and don't use prepared statements.

withBatch  { stmt ->
stmt.addBatch("insert into table (field1,field2) values('value1','value2')")
stmt.addBatch("insert into table (field1,field2) values('value3','value4')")
}

According to this link http://jira.codehaus.org/browse/GROOVY-3504 there is no way to use prepared statements directly from within batch. What is the best way to simulate this so I can avoid having to write my own code to avoid sql injection?