How do I calculate the shaHash for an xsd connection?

How do I calculate the shaHash for an xsd connection to match the one saved in livecycle designer es4?

This shaHash looks like a base64 sha1 hash, but it does not match the file's sha1 hash (calculated with tools on the web or in c#), nor does it match the hash of the document's root

It looks like either a salt is used, or the xml is changed by livecycle before the hash is calculated.

<connectionSet xmlns="http://www.xfa.org/schema/xfa-connection-set/2.8/">

   <xsdConnection name="DataConnection" dataDescription="Document">

      <uri>..\Correspondence.xsd</uri>

      <rootElement>Document</rootElement>

      <?templateDesigner fileDigest shaHash="dMPda1HmsbZtjFmzcTl7XaWa4tE="?></xsdConnection>

</connectionSet>