CSS Profile tax questions when separated and filing joint tax return

<p>My spouse and I are separated and doing our taxes as married filing jointly for 2010. I am the custodial parent and will be using my financial information. But when it comes to the tax information it is harder completing from a joint return. When I completed the FAFSA I found some verification instructions that detailed you could use a proportional method ( base tax you paid on the proportion of AGI that is attributed to you - ie 25% of AGI from me so 25% of taxes due are mine) to report the tax you owe. But on the CSS Profile form they want all sorts of detail on your tax form like your itemized deductions, etc. - does it make sense to due a similar proportion for all these detailed questions?? Please help!</p>