Substring xsl hithighlightedsummary in SharePoint

I have in hithighlightedsummary the tag this

<ddd /> Posted: 2/8/2011 10:04 PM <ddd /> Subject: some subject <ddd /> Some Text  <ddd />

I would like to 开发者_JAVA百科get the 'some subject' as a sub string. I have tried using "substring-after(hithighlightedsummary, 'Subject:')", But I don't know how to combine that with the <ddd /> tag.

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Did you mean something like this?

substring-after(
   //hithighlightedsummary
      /text()[
         contains(.,'Subject:')
      ],
   'Subject:'
)

Note: I've used an absolute expression because you didn't provide information about context.