The best document we've found thus far outlining the risks of utilizing HRAs to pay for employee's health insurance premiums is found on the following link:
http://www.smithandco.com/Smith_and_Co/Blog/Entries/2011/6/2_Employers_utilizing_HRAs_to_purchase_individual_policies_for_their_employees_may_be_violating_Federal_law_1_files/Broker%20Alert%20-%20HRA's%20and%20Individual%20Policies%205-11.pdf
The above mentioned document was written by attorney, Mark W. Major of Aurora, CO