How to write plain Greek in a text cell

If I create a text cell and type some greek text, most of the symbols are italics as if the cell had an Input style. It doesn't happen with latin characters. I recollect that it is impossible to fix it, but I can't find the source where I read it.

Perhaps someone knows a workaround ? The following screenshot is from Mathematica 8/Linux.

EDIT1: I just noticed that writing capital greek letters works fine (the letters are normal, not italics). The following screenshot is from Mathematica 9.0.1/OSX Mavericks.

Does that piece of information ring any bells to anyone on what might be the underlying problem ?

EDIT2: I also found this link describing a workaround by using custom modified unicode mapping files. I can't check it right now as I'm not near my Linux installation.

EDIT3: I did try it though in Mathematica 9.0.1/OSX (although the article talks about Mathematica 7&8/Linux), and it works great! Here is the relevant screenshot:

EDIT4: As pointed out by @ybeltukov in comments, the workaround is to set the third column of UnicodeFontMapping.tr to 0 (zero) for Greek letters so that the default font is picked for them.

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related –  cormullion Sep 20 '13 at 10:34
Similar question posted on Wolfram Community –  cormullion Sep 22 '13 at 8:40
Explanation of your last link: just set the third column of UnicodeFontMapping.tr to 0 for greek letters to choose the default font for them. –  ybeltukov Nov 1 '13 at 21:13
People, is it ethical to answer my own question that I put a bounty on ? –  Zet Nov 1 '13 at 21:13
It's always good to have an answer. I don't think you're allowed to award yourself a bounty, though... :) –  cormullion Nov 1 '13 at 22:13

Font for the Greek letters is defined in UnicodeFontMapping.tr:

...
0x03B1      N       -2      0x61        # \[Alpha]
0x03B2      N       -2      0x62        # \[Beta]
0x03B3      N       -2      0x67        # \[Gamma]
0x03B4      N       -2      0x64        # \[Delta]
0x03F5      N       2       0x65        # \[Epsilon]
0x03B5      N       -4      0xb6        # \[CurlyEpsilon]
0x03B6      N       -2      0x7a        # \[Zeta]
...


The third column defines the font. You can set it in corresponding lines to 0 (default font).

This approach was used in your link. Difference between the original file and the file in this link:

--- UnicodeFontMapping.tr       2012-10-26 12:11:10.000000000 +0200
+++ UnicodeFontMapping.tr.v8    2013-11-01 22:09:05.000000000 +0100
...
-0x03B1         N               -2              0x61            # \[Alpha]
-0x03B2         N               -2              0x62            # \[Beta]
-0x03B3         N               -2              0x67            # \[Gamma]
...
+0x03B1         N               0               0x61            # \[Alpha]
+0x03B2         N               0               0x62            # \[Beta]
+0x03B3         N               0               0x67            # \[Gamma]
...

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