Export Mailbox to .PST

Hello,

I wish all contents(Send,Receive,..etc) older than '06/21/2014' from all mailboxes should be exported to pst.

What to include additional to this cmdlet -

New-MailboxExportRequest -Mailbox <alias> -FilePath"\\Server\ShareFolder\<alias>.pst"

Please Guide.

Few details-

Name of Test mailbox - Demo

Mailbox Created on 06/10/2014

1) When I use the normal cmdlet,

New-MailboxExportReuqest -Mailbox Demo -FilePath "\\Server's IP\ShareFolder\Demo.pst it generates a pst of1505 KB.

2) When I use the cmdlet specifying today's date (For maximum output)

New-MailboxExportReuqest -Mailbox Demo -ContentFilter {(Received -lt "07/23/2014")} -FilePath "\\Server's IP\ShareFolder\Demo.pstit generates a pst only of 265 KB. (It means something is wrong somewhere)

3) Now the Strange thing is, the mailbox is created on 06/10/2014 (1.5 months old), when I use the cmdlet specifying the far previous date (3 months old)

New-MailboxExportReuqest -Mailbox Demo -ContentFilter {(Received -lt "04/23/2014")} -FilePath "\\Server's IP\ShareFolder\Demo.pstit again generates a pst of 265 KB. (It means something is wrong somewhere again)

Please Guide.

Thanks, Divyaprakash Koli