using a Hero tag in a pre-requisite

[Paragon]

In attempt to set up a couple 4e feats so they're properly checking for pre-requisites (specifically a couple that will let you take the feat if you have a high enough value in a specific attribute or are a particular race), I tried to do this in the pre-req script:

validif (#trait[attrCha] >= 13)
validif (hero.tagis[Race.rDragonbor] <> 0)

Its properly checking for the attribute, but not for the race. I'm guessing that you can't do a hero tag check in the script that way, but I'm not sure why, or how to construct it instead.

Any help?