samba - Feb 2013 - upgrade samba (3.0.33) to samba-3x (3.6.6) on Centos5

Hi
Related to my previous posting on joining win7 to a domain with samba-3.6.6
(which I finally managed to do!)
With Centos5 one has the option of installing either Samba which is 3.0.33
or Samba3x which is 3.6.6 with the latest updates to centos5.9
My own server was set up with samba3x and hence was able to attempt
connection of win7 PC

I have several customers with older installations using samba3.0.33. Last
year I tried updating one of them and it appeared the only way was to
remove samba (3.0.33) and then install samba3x.
This meant recreating all the shares and samba configuration and rejoining
everyone to the domain.
Is there an easier way of upgrading?
Regards
Peter Lawrie