I've been able to do this.  With no problem, in fact.  

I'm not sure why the samba package version would matter.  For
mounting, isn't everything important in smbfs?

I'm using a patched 2.4.5 kernel now, but had been using a Redhat 6.1
with no trouble.

Have you tried smbclient and mount from the shell to see what the
error messages are?  smbclient should give you some good information.

I'll try to help if you have more specifics.

R