http://socrates.berkeley.edu/~pinax/gre ... nload.html
Are others here familiar with this font? It puts some extra characters in the "Private Use Area" (PUA) of the Unicode encoding, and allows characters like alpha w/ macron + acute, that the normal fonts like Gentium don't.
You might use an editor that allows the entry of Unicode escape sequences. Or you can use a program like the Windows Character Map program to copy the characters into the cut-paste buffer, then paste them into a text file, and cut/paste them from the text file into your docs as needed. I do the latter. I have a text file that has a key to the Windows Greek keyboard sequences, in case I forget them. I put the PUA characters at the top of this file.