First, you need a directory in the file system where the files from the disc will appear. You might as well just create a new one. In Terminal, type:

mkdir cd

This creates a directory named "cd". You can name it whatever you want.

Now you need to determine the device name of the CD. Open Disk Utility, select the CD (the Mac side which is automatically mounted) and press the Info toolbar button. There should be a field labeled "Disk Identifier". The value to the right is the device name for the Mac side of the CD. It probably ends with "s1" or "s2". The device name for the CD as a whole is the device name of the Mac side minus the trailing "s1" or "s2".

To mount the Windows side of the CD, type this in the Terminal:

mount -t cd9660 -r /dev/<device name of CD> <name of directory you created>

For example, I've mounted a Windows/Mac hybrid CD. Disk Utility tells me that the Disk Identifier of the Mac side is "disk2s1s2". Therefore, I determine that the device name of the CD as a whole is "disk2s1". I've created a directory "cd" as the mount target. The command I issue is:

mount -t cd9660 -r /dev/disk2s1 cd

That should mount the Windows side of the CD.

Now you can use CrossOver to install the software from the Windows side. After you are done, you need to unmount the Windows side of the CD. The command to do that is:

umount <name of directory>

Following the example I gave above, I would do:

umount cd

After that, you can eject the CD normally.