[Xy-pic] Custom arrow steps over frame boundary

[John G. Michopoulos]

Dear All,

I used Exercise 25 of the Ref. manual to define a closed arrow head via the
code:

\newdir{|>}{!/7.5pt/\dir{|}
*:(2.5,-0.1)\dir^{>}
*:(2.5,+0.1)\dir_{>}} 

However, when I use it in the context of the code below the arrows drawn do
not stop at the boundary of the Circle frames ised but rather they step
over, thus geberating a not so great final result. 

I would greatly appreciate any help you might offer here!

Here's the Code:

---------------------------sinp-------------------------

\documentclass[jsco]{academic}
\usepackage{amssymb,amsfonts,amsbsy}
%
\input xy
\xyoption{ps} \xyoption{dvips} \xyoption{all}
%\xyReloadDrivers
%
% \usepackage[ps,dvips,all]{xy} %[ps,dvips,all]
% \SelectTips{cm}{}   %
%
\begin{document}
\shortauthor{ }
\shorttitle{ }
%
% \SelectTips{cm}{}
%
\def\Mnode#1{*+++=!C[o][F-:thicker]{#1}}
\def\Mnodez#1{*+++=!C[o][F=:thicker]{#1}}
\def\Lmnode#1#2#3#4{\Mnode{#1}="#1"
\POS="O"-(#3,#4)*!R\txt{\small #2} \POS"O" +(-#3,-#4) \POS"O"}
\def\Lmnodez#1#2#3#4{\Mnodez{#1}="#1"
\POS="O"-(#3,#4)*!R\txt{\small #2} \POS"O" +(-#3,-#4) \POS"O"}
\def\Arb#1#2{\ar @*{[thicker]}[#1]^{#2} }
\def\Arbo#1#2{\ar @{|>}  @*{[thicker]} [#1]^{#2} }
\def\Arbh#1#2{\ar @^{>}  @*{[thicker]} [#1]^{#2} }
%
\newdir{|>}{!/7.5pt/\dir{|}
*:(2.5,-0.1)\dir^{>}
*:(2.5,+0.1)\dir_{>}} % define open trig arrow head
%
% \xyoption{color}
% \xyoption{line}
Why do the closed arrows cross the node (04) boundaries?
$$
\xymatrix @W=2pc @H=4pc {  \Mnode{00} {\ar
@*{[thicker]}[rr]^-{\big{|_{uv}}}} & & % ++=!C[o][F-:thicker:red]
\Lmnode{01}{$E_{uv}$}{-7.0}{-6.0}
\Arb{rr}{l2} \Arbo{rd}{lo1} & \hole &\Mnodez{02} \\
& \Lmnode {06}{$T_{uv}$}{2.0}{-6.0} \Arbo{rr}{lo2} \Arb{ur}{l2}&&
\Mnode{04} \Arbh {rr}{ov1} & & \Lmnodez {05}{$S_{uv}$}{-7.0}{-6.0}
\Arbh {ll}{u1} }
$$
%
\end{document}
---------------------------sinp-------------------------
Thanks,

-john m

=========================================
Dr. John G. Michopoulos
Naval Research Laboratory, Code 6303
Computational Mutliphysics Systems Lab
Washington DC 20375, USA       
tel.202.767.2189  fax.202.767.9181
e-mail: john.michopoulos@nrl.navy.mil