G-brief2: Enumeration inside letter

This is really driving me crazy. Within Lyx I can use the option to include an enumated list in my letter (g-brief2). When I do, the list is put after closing and name (in code \end{g-brief} is inserted just before the enumeration).

I would like to inlcude the list inside my lettter text. How do I do that?

I have tried:

1. contacting the maintainer of g-brief2


2. including \usepackage{enumitem} in the preamble


3. Extensive fiddling with curly braces

Any help is greatly appreciated. I can, of course with to another letter class, but I really want to know what I could have done to resolve this (learning how Lyx/LateX works).

Regards, Matthijs

Here's a MWE:

% Preview source code

%% LyX 2.1.2 created this file.  For more info, see http://www.lyx.org/.
%% Do not edit unless you really know what you are doing.
\documentclass[12pt,english]{g-brief2}
\usepackage{mathpazo}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\pagestyle{empty}
\setlength{\parskip}{\medskipamount}
\setlength{\parindent}{0pt}

\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands.
 \newcommand{\LyxGruss}[1]
   { \Gruss{#1}{0.5cm} }

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\fenstermarken % prints address window marks
\faltmarken % prints folding marks
%\lochermarke % prints puncher marks 
\trennlinien % prints striplines
%\unserzeichen % prints "our ref" instead of "my ref"
\usepackage{graphicx}
\usepackage{enumitem}

\makeatother

\usepackage{babel}
\begin{document}



\NameZeileA{My company}


\AdressZeileA{My Address}


\AdressZeileB{My Country}


\RetourAdresse{My Adress}


\Adresse{{\large{}Address line 1}\\
{\large{}Address line 2}}


\Datum{1 december 2014}


\Betreff{Myreference}


\Anrede{Dear X,}


\LyxGruss{Regards,}


\Unterschrift{My name}
\begin{g-brief}
Letter first sentence.

Letter second sentence, includes an enumeration:\end{g-brief}

\begin{enumerate}
\item eerste
\item tweede
\item derde punt\end{enumerate}

\end{document}

My letter looks like this: