Dynamic Multi-select TV

I am looking to set a Mulit-select TV ’Default Value’ dynamically (i want the ID of the parent), but no approach I have tried works.

I found this post from 12/08: http://modxcms.com/forums/index.php/topic,31654.0.html

It looks like mutate_content.dynamic.php was hacked to accomplish this because

By default the @bindings @EVAL, @SELECT and so in the TV-default-value-field is not processed in the manager.

Is this still the case? Can this be accomplished without a hack?

Check this out!
http://modxcms.com/forums/index.php/topic,45224.msg268030.html#msg268030
http://modxcms.com/forums/index.php/topic,44285.0.html

...So you could set a modx [+placeholder+]
from a plugin onDocFormSave reading the parent value from the $_POST-var!