Opening Word Document in particular encoding

[managed coder]

There is a parameter which takes encoding type in Document.Open in
microsoft.office.interop.word. I tried using
Microsoft.Office.Core.MsoEncoding.msoEncodingUTF8" as encoding type.

But I get the following error:
"Parameter value was out of acceptable range"

Actually what am trying to do is converting word to HTML. Thus, I open Word
Document and save it as HTML file. Then read the HTML file format and store
it in database. But due to encoding problem, space characters is converted to
unrecognisable characters.