Click Start, click Run (Or just press WIN+R), and enter %LocalAppData%\Logitech\Logitech Gaming Software\profiles and then hit ENTER. This is where your profiles live. Unfortunately, they're named REALLY badly by default. Human Readable Profile Files contains information on how to properly rename these files.
Shut down LGS. Check Task Manager to make sure its down. (Look for LCore.exe)
Open up your favorite text editor.
Drag and Drop an XML file into that editor (Or, if XML files are associated with a text editor, just double-click the XML)
Take note on the 3rd line where it says "<profile " (NOT <profiles) and take note of what the Name= value contains. This is the profile text shown to you in the LGS.
Look for the line that has the <macros> tag. This line should be about 7 lines down, but your configuration options could vary that positioning.
Copy the raw contents of Macro-*.xml to your clipboard.
Paste to the line right after the <macros> line. Note that when LGS is restarted, this XML file is rewritten from scratch, so spacing of the XML text doesn't matter, just positioning. For the OCD, this means that the XML tags will realign themselves.
Save the XML file. Exit the editor if you wish.
Relaunch LGS.
Open up the profile you took note of above.
Confirm that the key binds are available.
Drag and Drop the F# key of your choosing to a G#-Key.