Opening PST file by provideing password through function

[Digambar Borse]

Hello All,
I'm woring with Outlook(useing Outlook Object Model & MAPI) ,
when I'm going to access the Password protected PST file ,It
pop ups a window to enter the Password ,but I want to give Password through
my program so that the windows wont come , I also tried it useing Extended
MAPI but cant get , I'm not understand how to use PR_PST_PW_SZ_OLD &
PR_PST_PW_SZ_NEW properties of PST file. I have Msg service admin interface
from my logon session.
So please tell me how I can give Password throgh a function call
to open the PST file so that it doesnt ask password for current session
anymore.
I'm tyring to use following code to provide password &
open PST file .

SPropValue MyProps[1];
MyProps[0].ulPropTag=PR_PST_PW_SZ_OLD;
MyProps[0].Value.lpszW=L"asdf";
hr = pMsgAdmin->ConfigureMsgService(&msuid,0,0,1,MyProps);

I'm giving correct password still its giving return Value
as MAPI_E_FAILONEPROVIDER i.e.
Password is worng or it requires more information.
I'm not getting whats going to be wrong , Please help
Thanking You,