Hi MSurfer,
Thank you for your post!
The behavior you are describing is intentional, but can be disabled by doing the following:
1. In the "VMware Fusion" menu and choose "Preferences".
2. Pick the "Keyboard & Mouse" preferences.
3. Select the "Windows 8 Profile" from the "Keyboard & Mouse Profile" drop down.
4. Choose the "Mac Host Shortcuts" tab.
5. Uncheck the "Enable Mac OS Host Keyboard Shortcuts" checkbox.
Following these steps should allow Command + Space to be seen by your Windows 8 guest. Please let us know if this does not work.
Thanks!
James