unable to generate 999 Acknowledgement by Biztalk server 2010

Hi,

i amm trying to generate 999 via biztalk server 2010.i did following steps

1)downlaod  hotfix that coontaing 999  schema nad 277_CA.

2)Add this schema to my vs 2010 project

3) create new receivepipleline and set property ‘”  US 999 INSTREAD OF 9997 ” to true and drop falt file disassemble file at assemble stage.

4)build and deployed in biztalk admin

5)set biztalk  admin envirement

when i run host in biztalk admin console,i got foollowing error

error 1   :         The ‘IsGeneratedAck’ attribute is not declared.

Error: 2             (Miscellaneous error) 5: X12_00501_999\ The element ‘X12_00501_999’ in namespace ‘http://schemas.microsoft.com/BizTalk/EDI/X12/2006’ has invalid child element ‘ST’ in      namespace ‘http://schemas.microsoft.com/BizTalk/EDI/X12/2006’. List of possible elements expected: ‘ST http://schemas.microsoft.com/BizTalk/EDI/X12/2006:AK1’.   MessageId:  {C67D5EFA-77AC-473E-B902-7A71C04680D4} InstanceID: {3D02C0C0-E11F-4250-A9A4-ACDF2C3B24F3}

what is wrong?

waiting for reply