How will you do that?
Easy!
Open up your terminal and type
sudo gedit /usr/share/applications/bitcoin-qt.desktop
Find the following line
Exec=/usr/bin/bitcoin-qt
and replace it with
Exec=APPMENU_DISPLAY_BOTH=1 bitcoin-qt
Save the file.
Open Unity HUD and start Bitcoin-qt.
If the above doesn't work, then try the following workaround.
Start it from the terminal using the following command
APPMENU_DISPLAY_BOTH=1 bitcoin-qt &
You should have at least one of the menus available now.
