Does index based on text with 'en_US.utf8' collation support like query?

Hi,

I found that queries like "select * from tbl where col1 like 'abc%'" will use index only when the col1(and the index)
use'C' collation. If I use 'default' which is 'en_US.utf8' in my database, the equation condition will use the index
butlike query will not. 

I also tried to specify the collation explicitly: like ('abc%' collate 'en_US.utf8'), not work too.

Is that only 'C' collation support 'like' query or I missed something in my sql? Or do I need to install something
additionalto support index on other collation? 

Thanks in advance.