Document expiration problem for separate users

[Vinita]

Hi,

I am using office automation apis to apply RMS protection.
I want to set the different expiration date for different users.
i am using following code


DateTime dtExpireDate = new DateTime(2008, 10, 8);
Microsoft.Office.Core.MsoPermission per =
Microsoft.Office.Core.MsoPermission.msoPermissionPrint;
DateTime dtExpireDate1 = new DateTime(2008, 11, 8);
Microsoft.Office.Core.MsoPermission per1 =
Microsoft.Office.Core.MsoPermission.msoPermissionChange;


oWordDoc.Permission.Add("user1.abc@domainname", per, dtExpireDate);
oWordDoc.Permission.Add("user2.abc@domainname", per1, dtExpireDate1);
and then i save the document.


But when both users check that document, then same expiration date
of( 2008, 10, 8); is peresent.


How can i set the the separate expiration date for sepate users for
the same document.
Please hepl me in this.


Thanks and Regards,
Vinita.