Callback support in JSON output for the markup validator

This http://www.w3.org/QA/2008/08/markup_validator_updated.html post
describes json support for the Markup validator.
It mentions that it followed the design of validator.nu

One of the feature's that validator.nu supports for it's JSON output
is  JSONP or JSON callback parameter.
Essentially the entire json is rapped in a function call that you
specify, very nice for some specific use cases.

I havn't found this feature to be supported on the markup validator.
Have I missed something?

If not I would like to submit a feature request to add " callback " as
a parameter to the validator when output is set to "json".

Thank you,
Brian Gianforcaro