Reg. downpayment wrong calculation

Dear Friends

I am paying down payment through ME21N,ME2DP then I am paying 1000 rs + 10% tax amount = 1100 rs should be calculated,

but system calculated as vendor a/c 900 Dr , bank a/c Cr 900, vat a/c 100 Dr and TDS 100 Cr.

Please help me what settings required to calculate as mentioned above.

I checked tax code,condition type ,pricing procedure and tax procedure,everything is correct.

Purchase value 10000 + 10% tax = 11000, then down payment 1000 rs + 10% tax.

Thanks

Rajakumar.K