How can two unmarried buyers allocate the Worker, Homeownership and Business Assistance Act of 2009?

How can two unmarried buyers allocate the Worker, Homeownership and Business Assistance Act of 2009 if one qualifies for the $8,000 first time home buyer tax credit and the other qualifies for the $6500 repeat homebuyer credit?  The buyers can allocate the tax credit in any reasonable manner, provided neither claims a tax credit higher than the one they qualify for and the home purchase does not yield a total of more than $8,000 in tax credits.  For example, the repeat home buyer could claim $6,500 and the first-time home buyer could claim $1,500.  Alternatively, both buyers could claim a $4,000 tax credit.