VSA Accounting

How does one refer to VSAs in the accounting queries in sql.conf? I figure it would just be the name of the attribute from the dictionary, but what if there's a VSA name the conflicts with a standard name (e.g. "Realm")? Is there a prefix that can be used to differenciate them? Also, what's a better method: extending the radacct table to include these VSAs, or using a table specifically for the VSAs?