Searching SimpleDB in a case-insensitive way

Since Amazon SimpleDB doesn't provide case-insensitive query, what w'd be the best way to do a case insensitive search for attributes in simpleDB ?

One thing that can be done is including a separate attribute that is the lowercase version of each string, and then use a 'like' query but it will involve a lot of duplication.Is there any elegant way to do the same ?

EDIT
I first tried keeping a separate attribute that was the lowercase version of text to be searched, and then used 'like' query, but the 'like' is not really fast enough for stuff i'm building and also the idea of adding redundant data and complexity to the application is not cool. So i integrated elasticsearch, and it is working quite fine so far + this gives more control over search.