Is it possible to convert a home equity loan?

[John Wisdom]

We used a home equity loan from our primary residence to purchase our rental property. It was great because there were no closing costs, the interest rate was much lower and the down payment requirement was much more flexible. The only problem now is that I am unable to deduct the mortgage interest from the rental income since the loan was not used to buy, repair or improve our primary residence. Is there any way around this? Is it possible to convert the home equity loan into a conventional loan using the investment property as the collateral?