# shifting/aligning nodes with pst-tree

The following code produces nice trees with pst-trees. I have to gloss the leaves of the tree, so I put tabular environments in there and added the glosses. The problem is that the code does not align the nodes towards the top but centers them. This means that the N above David is between is and AUX. But it should be at the hight of is as in the left example. Is this possible?

\documentclass{article}

\usepackage{pst-tree}

\psset{nodesep=5pt}
\psset{linewidth=0.5pt}

\makeatletter
\def\tree{\@ifnextchar[{\@tree}{\@tree[top]}}
\def\@tree[#1]#2#3{%
\renewcommand\psedge{\ncdiag[arm=0,angleA=270,angleB=90,linewidth=.5pt]}
\pstree[levelsep=*2.8ex,nodesep=3pt,treesep=.5cm]{\TR[name=#1]{\small #2}}{#3}}

\def\le{\@ifnextchar[{\@le}{\@le[lex]}}
\def\@le[#1]#2{\renewcommand\psedge{\ncdiag[arm=0,angleA=270,angleB=90,linewidth=.5pt]}
\TR[name={#1}]{\begin{tabular}{@{}c@{}}#2\end{tabular}}}
\makeatother

\begin{document}

\tree[a]{IP}{%
\tree{NP}{\tree{N$'$}{%
\tree{N}{\le{David}}}}
\tree[b]{I$'$}{%
\tree[c]{I}{\le{is}}
\tree[d]{VP}{\tree[e]{V$'$}{\tree[f]{V}{\le{yawning}}}}}}%
\hfill
\tree[a]{IP}{%
\tree{NP}{\tree{N$'$}{%
\tree{N}{\le{David\\David}}}}
\tree[b]{I$'$}{%
\tree[c]{I}{\le{is\\\textsc{aux}}}
\tree[d]{VP}{\tree[e]{V$'$}{\tree[f]{V}{\le{yawning\\gloss}}}}}}%

\end{document}

