I'm not 100% positive if it's a function of Kentico that can be overwritten with a Custom Search Index or not.
But a quick question, what is the case for having the value saved as is? Usually lucene will lowercase search results so it's quicker to search, when you display your results though you can call any field you want in the transformation.
Search fields are for finding matches, then the "Content" value is saved as is to display the result summary, along with any value you need through the <%# GetSearchValue("MyFieldName") %> which pulls from the document content, not necessarily the smart search index.