From the IRS website:
Q. Can a taxpayer claim the first-time homebuyer credit if the purchase is pursuant to a seller financing arrangement (for example, a contract for deed, installment land sale contract, or long-term land contract), and the seller retains legal title to secure the taxpayer’s payment obligations?
A. If the taxpayer obtains the “benefits and burdens” of ownership of a residence in a seller financing arrangement, then the taxpayer can claim the credit even though the seller retains legal title. Factors that indicate that a taxpayer has the benefits and burdens of ownership include: 1. the right of possession, 2. the right to obtain legal title upon full payment of the purchase price, 3. the right to construct improvements, 4. the obligation to pay property taxes, 5. the risk of loss, 6. the responsibility to insure the property and 7. the duty to maintain the property. (New 7/2/09)