[xsl] Phonetic Sorting for Japanese Language

[Subhojit Chatterjee <s.chatterjee@xxxxxxxxxx>]

I want to sort countries ( in Japanese language-  Katakana/Kanji  script)
by Phonetic Sort order (and NOT by Alphabetic Sort order) . The country
names are picked from a xml  of the form as below
...
<countryname>エルサルバドル</countryname>
<countryname>オーストリア</countryname>
<countryname>韓国 </countryname>
<countryname></countryname>
<countryname>ギリシ</countryname>
<countryname>オランダ</countryname>
...
I tried to sort in XSL as below but none of these show the correct sort
order.
.......
<xsl:sort select="." lang="ja" />
.......
...OR ....
<xsl:sort select="." lang="ja-JP" />
.......
Can anybody please give light on this issue ?