Adding fields to my letter layout

[Andre Berger]

My own letter layout is still unfinished (better: unfurbished) yet
because I don't really understand the LyX concept. I'd like to add an
item to a letter layout, like "\closing" (you know what I mean),
called "\Anlagenzahl". It should do a "\renewcommand". Taken the 

# Closing style definition
Style Closing
  CopyStyle             Letter
  LatexType             Command
  LatexName             closing
  KeepEmpty             0
  TopSep                1.5
  BottomSep             1.5
  ParSep                1.5
  Align                 Left
  AlignPossible         Left
  LabelString           "Grussformel:"
End

how can I put a "\renewcommand{\Anlagenzahl}{What the user fills in}" into
this construction?

Thanks,

Andre

-- 
Andre Berger <[EMAIL PROTECTED]> from Bonn, Germany