How to make LIKE to use index in "abc%" query?

Hello.

I run

explain analyze
SELECT id FROM "table" WHERE name LIKE 'dt%';

having a btree index on "name" column. But unfortunately it uses seqscan
instead of index scan, it's too slow.

I had read some mailing archives about that problem, but have not found a
solution. How to fix this LIKE behaviour withour re-creation af the whole
database? Is it possible?

I use windows-1251 locale, not C locale.