UPDATE: You can select the 32bit voices for system use, you need to use the 32 bit version of the control panel applet. Try this in the search box.
%windir%\syswow64\speech\speechux\sapi.cpl
click the icon you now have the 32 bit control to speak to windows
You should see your 32bit voices provided they are SAPI5. This works with ATT Natural voices. This would solve your 32bit apps issues