\documentclass[twoside]{scrartcl}
\usepackage[frame]{xy}
\usepackage{tabularx}
\usepackage[latin1]{inputenc}
\setlength{\voffset}{0.5cm}
\setlength{\hoffset}{-2.0cm}
\setlength{\topmargin}{0cm}
\setlength{\headheight}{0.5cm}
\setlength{\headsep}{1cm}
\setlength{\topskip}{0pt}
\setlength{\oddsidemargin}{1.0cm}
\setlength{\evensidemargin}{1.0cm}
\setlength{\textwidth}{19.2cm}
\setlength{\textheight}{24.5cm}
\setlength{\footskip}{1cm}
\setlength{\parindent}{0pt}
\renewcommand{\baselinestretch}{1}
\begin{document}

\newlength{\descrwidth}\setlength{\descrwidth}{10cm}

\newsavebox{\hdr}
\sbox{\hdr}{
  \fontfamily{cmss}\fontsize{10pt}{12pt}\selectfont

  \parbox{\textwidth}{
    \parbox[b]{12cm}{
      <%company%>
      
      <%address%>}\hfill
    \begin{tabular}[b]{rr@{}}
    Telephone & <%tel%>\\
    Facsimile & <%fax%>
    \end{tabular}

    \rule[1.5ex]{\textwidth}{0.5pt}
  }
}
    
\fontfamily{cmss}\fontshape{n}\selectfont

\markboth{<%company%>\hfill <%invnumber%>}{\usebox{\hdr}}

\pagestyle{myheadings}
%\thispagestyle{empty}     use this with letterhead paper

<%pagebreak 90 27 48%>
\end{tabular*}

\newpage

\markright{<%company%>\hfill <%invnumber%>}

\vspace*{-12pt}

\begin{tabular*}{\textwidth}{@{}p{\descrwidth}@{\extracolsep\fill}rl@{}}
  \textbf{Description} & \textbf{Qt'y} &
    \textbf{Unit} \\
<%end pagebreak%>


\fontfamily{cmss}\fontsize{10pt}{12pt}\selectfont

\vspace*{2cm}

<%shiptoname%>

<%shiptoaddr1%>

<%shiptoaddr2%>

<%shiptoaddr3%>

<%shiptoaddr4%>

\vspace{3.5cm}

\textbf{P A C K I N G} \parbox{0.3cm}{\hfill} \textbf{L I S T}

\hfill
\begin{tabular}[t]{l@{\hspace{0.3cm}}l}
  \textbf{Date} & <%invdate%> \\
  \textbf{Number} & <%invnumber%> \\
  \textbf{Customer} & <%customer_id%>
\end{tabular}

\vspace{1cm}

\begin{tabular*}{\textwidth}{@{}p{\descrwidth}@{\extracolsep\fill}rl@{}}
  \textbf{Description} & \textbf{Qt'y} & \textbf{Unit} \\
<%foreach number%>
  <%description%> & <%qty%> & <%unit%> \\
<%end number%>
\end{tabular*}


\parbox{\textwidth}{
\rule{\textwidth}{2pt}

\vspace{12pt}

<%if notes%>
  <%notes%>
<%end if%>

}

%\vfill
%\centerline{\textbf{Thank You for your valued business!}}

%\renewcommand{\thefootnote}{\fnsymbol{footnote}}

%\footnotetext[1]{\tiny
%Items returned are subject to a 10\% restocking charge.
%A return authorization must be obtained from <%company%> before goods are
%returned. Returns must be shipped prepaid and properly insured.
%<%company%> will not be responsible for damages during transit.}

\end{document}