Tags and defining custom attributes

I have a need to create an attribute to store tags. I expected to define a custom attribute (used text, html, and everything else) and then on the presentation specify a kind of tags and my custom attribute. Great. Unfortunately, nothing appears on my presentation. If I flip my presention to use text, html, etc, my attribute appears. Switch to tags, nothing.

Am I correct in I can't use tags in a custom attribute at this point? When will I be able to? This is functionality that is very useful and quite important and I have spent hours hoping to make it work to no avail.

Please advise.