PowerShell Workflow Activity - Strange happenings when trying to use Target's (Person) ObjectSID

Hello, 

I am using FIM 2010 R2 and the latest version of thePowerShell Workflow Activity 

I am having trouble when retrieving the Target's (Person) ObjectSID 

At first I tried to add it as a value in the Workflow Dictionary using a Function Evaluator before the PowerShell activity. However every time I did this the PowerShell wouldn't fire...? I confirmed that ObjectSID was the issue by running the same PowerShell Activity but changing and/or removing ObjectSID lookups... All those in the 'test' set have an ObjectSID as imported from Active Directory 

I next tried to use the ObjectSID as retrieved when you retrieve the entire Target object. The following is an example of that code:

$Target= Export-FimConfig -Custom ("/*[ObjectID='{0}']" -F $fimwf.TargetId.Guid) | Convert-FimExportToPSObject
$Target.ObjectSID
AQUAAAAAAAUVAAAA1u7/iCIBtngCifraqe4CAA==

The final line of text is the format with which SIDs are being returned.... I need to be able to double check against Active Directory this user exists and cannot do that with the SID in its 'current' format...

Does anyone know why my first attempt happened or ideally how to get the expected SID format from what I currently have...? 

Thanks 
M12