In latvian alphabet there can be accented letters A E I U (and others). Accented letters should follow after simple letters according the rules of alphabet, but they don't. For now, Firebird does not sort them, and our clients are unhappy with that.

For now it works that way:
A and Ā, a and ā - no difference in sorting
E and Ē, e and ē - no difference in sorting
I and Ī, i and ī - no difference in sorting
U and Ū, u and ū - no difference in sorting

Currently it works as described here: http://www.collation-charts.org/firebird20/fb203.WIN1257.WIN1257_LV.html

Should be:
AĀ, aā
EĒ, eē
IĪ, iī
UŪ, uū

Link to latvian alphabet in Wikipedia: http://lv.wikipedia.org/wiki/Latvie%C5%A1u_alfab%C4%93ts

I can provide you additional information and/or test DB and if you need.

Can this be fixed in Firebird 2.5 Final? Or maybe there is way to fix it also for older FB versions?

p.s. I tried to create custom collation with ACCENT, but it doesn't work as expected.

Thank you in advance.

Script to reproduce the problem in attachment. Script creates table with 2 fields: "TEXT" - latvian text, "SORTIROVKA" - text field with right indexes. Script is saved in UTF-8 encoding.

To reproduce problem, use query:
select *
from TEST_LV_SORT tls
order by tls.text COLLATE WIN1257;

or

select *
from TEST_LV_SORT tls
order by tls.text COLLATE test_lv;


Also I attached backup file for DB with test data (same as in script). Backup image (gbak) for Firebird 2.5.