I have 64-bit Windows and I'm trying to use ReWire with Mixcraft 6, but it's not listed as a ReWire application!

Since Mixcraft 6 is a 32-bit application, it needs to communicate with the 32-bit version of Reason. If you have 64-bit Windows, Reason will automatically install itself as a 64-bit application and it will use 64-bit ReWire.

Here are instructions for installing a 32-bit version of Reason:

1. Open the Reason DVD (or the Reason download package, if you have downloaded the program from the web)
in Windows Explorer.

2. Right-click the "Install Reason.exe" file and select "Create Shortcut".
If the file is on the DVD, you will be asked if you want the shortcut to be placed on the desktop - click Yes.

3. Locate the shortcut you just created, right-click it and select "Properties".

4. On the "Shortcut" page of the Properties dialog, locate the Target field and add " /32" (without the quotes) at
the very end. The Target field should say 
"D:\Install Reason.exe" /32
(although the drive letter may not be "D", depending on your setup).

5. Click OK. 

6. Double click the shortcut file to install a 32-bit version of Reason. 

The installed Reason version will have the name "Reason (32)" on the Start menu and desktop. You can have the
regular 64-bit version installed at the same time if you like.