integrate sharepoint authentication with office 365

How can i integrate Sharepoint authentication into my BPOS setup? i want users to login to Sharepoint using the same credentials they use to login to BPO开发者_StackOverflow社区S. This is to avoid having to use seperate FBA for Sharepoint 2010.

Do note that the Sharepoint i used is Sharepoint 2010 enterprise and not Sharepoint Online.

Thanks

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Depends a bit on your scenario and if you are using identity federation.

If you are federating your identities to the cloud/office365 using DirSync then you have SSO to both on-premise and SSO.

If you only have MSOnline users, ie no AD on-premise or at least not syncing it, then you need to set up your on-premise SP2010 with claims support and set up a trust relationship with the Office365/SPOL STS. (At the moment since Office 365 is in private beta and under NDA - that's about what I dare to share...but it's doable)