How do I correctly index Spanish language documents using Solr?

More specifically, I have tried two different "character folding" techniques to index non-ASCII characters, and neither one seem to work 100% of the time. Both techniques allow me to find some accented character but not others. 

For example, I use the ASCIIFoldingFilterFactory like this:

    <fieldType name="text_general" class="solr.TextField" positionIncrementGap="100" multiValued="true">
     <analyzer type="index">
      <tokenizer class="solr.StandardTokenizerFactory"/>
      <filter class="solr.ASCIIFoldingFilterFactory"/>
      <filter class="solr.StopFilterFactory" words="stopwordsspanish.txt" ignoreCase="true"/>
      <filter class="solr.LowerCaseFilterFactory"/>
     </analyzer>
     <analyzer type="query">
      <tokenizer class="solr.StandardTokenizerFactory"/>
      <filter class="solr.ASCIIFoldingFilterFactory"/>
      <filter class="solr.StopFilterFactory" words="stopwordsspanish.txt" ignoreCase="true"/>
      <filter class="solr.SynonymFilterFactory" expand="true" ignoreCase="true" synonyms="synonyms.txt"/>
      <filter class="solr.LowerCaseFilterFactory"/>
     </analyzer>
    </fieldType>

Or I use the MappingCharFilterFactory like this:

    <fieldType name="text_general" class="solr.TextField" positionIncrementGap="100" multiValued="true">
     <analyzer type="index">
      <charFilter class="solr.MappingCharFilterFactory"  mapping="mapping-FoldToASCII.txt"/>
      <tokenizer class="solr.StandardTokenizerFactory"/>
      <filter class="solr.StopFilterFactory" words="stopwordsspanish.txt" ignoreCase="true"/>
      <filter class="solr.LowerCaseFilterFactory"/>
     </analyzer>
     <analyzer type="query">
      <charFilter class="solr.MappingCharFilterFactory"  mapping="mapping-FoldToASCII.txt"/>
      <tokenizer class="solr.StandardTokenizerFactory"/>
      <filter class="solr.StopFilterFactory" words="stopwordsspanish.txt" ignoreCase="true"/>
      <filter class="solr.SynonymFilterFactory" expand="true" ignoreCase="true" synonyms="synonyms.txt"/>
      <filter class="solr.LowerCaseFilterFactory"/>
     </analyzer>
    </fieldType>

In both cases I can search for and find some words with non-ASCII characters and some not. For examnple, I can find documents with the word "presentará" but not necessarily all of them. I know my corpus includes the word "señor" but I can never find it.

What might I be doing wrong?

--
Eric Morgan