UPDATE on the HHonors "option".....

The National Website (very poor functionality and features) appears to say that you can get HHonors points but offers no detailed information nor a way to request HHonors points as credit, despite the "vague" wording you can find under the Partner Rewards Program section.

I called the Customer Service line and after a long hold the rep told me that the HHonors option is only available through National (which apparently is owned by Enterprise).... so basically it seems Im stuck with Enterprise points for my rental.... (sigh)