got a reply from propellerheads,created a copy of the Install Reason.exe file to the desktop,renamed it in target field(right click >properties).
In the “Target” field, add ” /32″ (without quotes, keep the leading space) at the very end>Click OK.
Double click the shortcut to run the Reason installer in 32-bit mode.
Reason now installed as a 32 bit program.
Before i did this,i installed cubase in 32 bit mode(gives you the option when installing at the beginning to install in either 32 or 64 bit mode).
Now i can sync cubase and reason with Rewire,Rewire channels now show in cubase.
took a while to get there but eventually it all worked out.