[Zope] how to get the rid from a ZCatalog object?

[Konstantinos Margaritis]

I have a ZCatalog object named images.
I tried this

<dtml-in images>
  <dtml-var "images.getpath(id)">
</dtml-in>

The problem is that getpath() doesn't want the id, but the rid.
How do I acquire this knowing the id?

Thanks