Apostrophe in date format in Ubuntu/Gnome

[Iñigo Varela]

In Asturian language, like in English, is common the use of Apostrophe,
i.e. (I am--> I'm; do not-->Don't)
In this way, Asturian use Apostrophe with word "de", when the following
word begins with vowel:

ASTURIAN	ENGLISH

19 de xineru	(19th of January)
19 de febreru	(19th of February)
19 de marzu	(19th of March)
19 d'abril	(19th of April)
19 de mayu	(19th of May)
19 de xunu	(19th of June)
19 de xunetu	(19th of July)
19 d'agostu	(19th of august)
19 de setiembre	(19th of september)
19 d'ochobre	(19th of october)
19 de payares	(19th of november)
19 d'avientu	(19th of december)

Today is 7th of december, and in my calendar I can see "7 de avi". The
correct form should be: "7 d'avi".
I have found in gdm and gnome-panel that the format for date is:

%a, %e de %b -----> llu, 7 de avi  (mon, 7th of dec), instead of correct
form that must be "llu, 7 d'avi"

Obviously, this format works for a few months, but it doesn't work in
abril (April), agostu (August), ochobre (October), and avientu
(December)

How can we do for use the apostrophe with the name of months that begins
with vowel? Any language with same problem?