Reg. Tax calculate tick in MIRO

Dear Experts

During MIRO if I tick the Tax calculation tab tax is not calculated but tax is calculate if I put either VAT or Excise any one in PO,if I use both taxs the tax calculation tab is not working in MIRO,Pls help me and then in MIRO simulation entry the entries are like this

1 K RAJA DESIGNERS / 641687 COIMBATORE 0.00 INR

2 S 504007 GR/IR Clearing - Poly Bags 104.12 INR 4500052909 10

G/L for vendor is not there,how to assign ?

thanks in advance

Rajakumar.K