I ran into a couple of good articles on setting up Claims Based Authentication on SharePoint 2010 using Azure. In these pages Mike Hacker runs you through all the settings in the Azure ACS panel and SharePoint 2010.
The only problem I found after following these guides was that the logon token cache expiration window expired way too fast. To solve this you’ll have to set the LogonTokenCacheExpirationWindow to 1 minute instead of 10.
- Open the SharePoint 2010 Management Shell and run the commands below
$StsC = Get-SPSecurityTokenServiceConfig
$StsC.LogonTokenCacheExpirationWindow = (New-TimeSpan -Minutes 1)