Windows Server R2 and SMB resources. error, problem, not connect

hi

We had a w2k3 cluster.
If , We needed to connect from another worksgroup computer We did
\\clustername\resource.

With W2k8 R2 I need to write:
\\clustername.domain\resource in the computers out the domain (of course We connect with a domain account.

And I need to add in the host file the IP for the clustername.

So, take a look

sanTos