Security :: Specify Password For A Password Protected Ppt File Through Vb.net?

Am trying to open a .pps/.ppt file through my vb.net code.....due to secure reasons this file is password protected,

However i will not like the end user to put a password when accessing through my application.

Hence i want to pass a password as a parameter while open such a password protected file.

Here is my code.

Reference URL: http://support.microsoft.com/kb/303717/EN-US/
Dim oApp As Microsoft.Office.Interop.PowerPoint.Application
Dim oPres As Microsoft.Office.Interop.PowerPoint.Presentation
Dim objpresset As Microsoft.Office.Interop.PowerPoint.Presentations
oPres = objpresset.Open(filename, Microsoft.Office.Core.MsoTriState.msoCTrue, Microsoft.Office.Core.MsoTriState.msoCTrue, Microsoft.Office.Core.MsoTriState.msoCTrue)

Where can i provide password while opening a ppt file...