SharePoint 2013 Data View Web Part with SOAP connection to get current user's "myLink"

Question

Hi I am new with SharePoint. We have a Data View Web Part that uses a SOAP Service to get the current user's mylinks and display them. It was working on SharePoint 2010. After we have migrated to SP2013 the DVWP stop working. I found out that the issue is the the parameter used in this DVWP uses the ServerVariable(AUTH_USER) to get the user XXXX\YYYYY value which will be use to retrieve the current user'd links. However this parameter starts with 0#.w| instead only XXXX\YYYYY. I have searched online for a solution and I can find anything that would help. How can I retrieve the right accountName and pass it to the SOAP Service?