Useful links:

New-ExchangeCertificate cmdlet on Microsoft Technet: http://technet.microsoft.com/en-us/library/aa998327.aspx
Get-ExchangeCertificate cmdlet on Microsoft Technet: http://technet.microsoft.com/en-us/library/bb124950.aspx
Import-ExchangeCertificate cmdlet on Microsoft Technet: http://technet.microsoft.com/en-us/library/bb124424.aspx

 
We need certificates to publish internal Exchange 2007 services (like OWA, ActiveSync, OutlookAnywhere) using Microsoft ISA 2006. We want to get a private SLL certificate from internal Certification Authority (CA). We have to generate a certificate request, for example [...]

Described method regards access to user mailbox on Microsoft Exchange 2007 mail Server. We presume that our user has got proper privileges to open mailbox for this profile.
 
To open mailbox of a certain user or joint users you can use one of following methods:
1. Login to your own account on OWA, for example:
https://owa.company.local/owa and open [...]