If you are concerned with matching Upper/Lower Case characters ...
have a look at string.Compare
perhaps try something like this in a test method that you can pass the docCollection and NameToTest to ...
public static Document GetDocumentFrom ( DocumentCollection dc, string docName )
{
foreach ( Document doc in dc ) {
if ( string.Compare( docName, doc.Name, true ) == 0 )
return doc;
}
return null;
}