title: UIWebView does not open ms word (doc) and ms excel (xls) files
body: <p>I'm developing an application for iPad using XCode 3.2.5 iOS SDK 4.2.  This application requires to open PDF, DOC and XLS files and preview them to the user.</p>
  
  <p>I'm trying to open them with the UIWebView control. Only PDF files are being opened correctly. When opening DOC or XLS I got a black empty view.
  This is happening in Simulator and Device. </p>
  
  <p>What am I doing wrong?</p>
  
  <p>Here is the code:</p>
  
  <pre><code>-(void)prepareToShow:(NSString*)filePath fileType:(NSString*)fileType request:(NSURLRequest*)request{
  
  UIWebView *webView = (UIWebView*)self.view;
  self.actualFilePath = filePath;
  
  NSLog(@"File Path %@",filePath);
  
  NSString *mimeType = @"";
  if ([fileType caseInsensitiveCompare:@"PDF"]==NSOrderedSame){
      mimeType = @"application/pdf";
  } else  if ([fileType caseInsensitiveCompare:@"DOC"]==NSOrderedSame){
      mimeType = @"application/msword";
  } else  if ([fileType caseInsensitiveCompare:@"XLS"]==NSOrderedSame){
      mimeType = @"application/vnd.ms-excel";
  }
  
  [webView loadData:[NSData dataWithContentsOfFile:filePath] MIMEType:mimeType textEncodingName:@"UTF-8" baseURL:[NSURL URLWithString:@"http://www.google.com"]];
  
  }
  </code></pre>