Hi Piyush, I am not sure what "http://authentication.husqvarna.net " is - is that some type of authentication portal that you have set up that SDM is using?
If so, then most likely its just the URL that you are pointing users to when they go to access SDM. You should be able to get the SDM login page itself by going to http://servername:8080 or http://servername/CAisd/pdmweb.exe - in other words, NOT hitting your authentication portal, but hitting SDM directly.
This may just require a DNS change to point your "servicedesk.xcompany.com" url to SDM rather than to the authentication portal.
Let us know,
Jon I.