EWS - retrieving PR_STORE_ENTRYID value

Hi,

I am trying to retrieve PR_STORE_ENTRYID value on a mailbox.

Here is the code snippet.

var ourProps = new PropertySet(BasePropertySet.IdOnly);
            var PR_STORE_ENTRYID = new ExtendedPropertyDefinition(4091, MapiPropertyType.Binary);
            ourProps.Add(PR_STORE_ENTRYID);
            Folder rootFolder = Folder.Bind(service, WellKnownFolderName.Root, ourProps);
                                  object propVal = null;
            if (rootFolder.TryGetProperty(PR_STORE_ENTRYID, out propVal))
            {

                // blablabalba

            }


The byte array that EWS returns me is 124 bytes.
Here is the converted string:
0000000038A1BB1005E5101AA1BB08002B2A56C20000454D534D44422E444C4C00000000000000001B55FA20AA6611CD9BC800AA002FC45A0C0000006578323031332D62652D30312E6C61627A65726F2E6D316465762E636F6D0045DC3FDD3E452141997812ED19A12EF55926AE630700304EAD87CD5D218DE025
While OutlookSpy and MfcMAPI show that PR_STORE_ENTRYID has 244 bytes.
0000000038A1BB1005E5101AA1BB08002B2A56C20000454D534D44422E444C4C00000000000000001B55FA20AA6611CD9BC800AA002FC45A0C00000064643366646334352D343533652D343132312D393937382D313265643139613132656635406C61627A65726F2E6D316465762E636F6D002F6F3D456D734465764F7267616E697A6174696F6E2F6F753D45786368616E67652041646D696E6973747261746976652047726F7570202846594449424F484632335350444C54292F636E3D526563697069656E74732F636E3D62326531343437353635346534393331386562353136323037646238646439302D41646D696E00
I am not sure why EWS returns different byte array value. 
Does anyone know why this is the case? 
Thanks.