Hello, I have used your input file, "slightly" modified, with Minion Pro and a font that I am still developing and it gives the expected results.
BTW, I don't think I have Gentium and I am using XeTeX, Version 3.1415926-2.5-0.9999.3 (TeX Live 2013) A.S. ---------------------- Apostolos Syropoulos Xanthi, Greece http://obelix.ee.duth.gr/~apostolo http://asyropoulos.wordpress.com http://hypercomputation.blogspot.com/
greek.tex
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greek.pdf
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