Unfortunatly, we are not Latex nor Tikz expert here.
However, we have build a new beta https://dl.dropboxusercontent.com/u/13064071/plantuml.jar
This beta adds some information when links are present in the source.
With you example, this beta generates the following file:
\documentclass{article}
\usepackage{tikz}
\usepackage{aeguill}
\usepackage{hyperref}
\begin{document}
% generated by Plantuml 8028beta1
\definecolor{plantucolor0000}{RGB}{168,0,54}
\definecolor{plantucolor0001}{RGB}{254,254,206}
\begin{tikzpicture}[yscale=-1]
\draw[color=plantucolor0000,line width=1.0pt,dash pattern=on 5.0pt off 5.0pt] (29pt,39.6094pt) -- (29pt,89.9609pt);
\draw[color=plantucolor0000,line width=1.0pt,dash pattern=on 5.0pt off 5.0pt] (85pt,39.6094pt) -- (85pt,89.9609pt);
\draw[color=plantucolor0000,fill=plantucolor0001,line width=1.5pt] (8pt,3pt) rectangle (47pt,34.6094pt);
% should have a box from (8pt,3pt) to (47pt,34.6094pt) that links to http://www.yahoo.com
\node at (15pt,10pt)[below right]{Bob};
\draw[color=plantucolor0000,fill=plantucolor0001,line width=1.5pt] (8pt,88.9609pt) rectangle (47pt,120.5703pt);
% should have a box from (8pt,88.9609pt) to (47pt,120.5703pt) that links to http://www.yahoo.com
\node at (15pt,95.9609pt)[below right]{Bob};
\draw[color=plantucolor0000,fill=plantucolor0001,line width=1.5pt] (61pt,3pt) rectangle (105pt,34.6094pt);
\node at (68pt,10pt)[below right]{Alice};
\draw[color=plantucolor0000,fill=plantucolor0001,line width=1.5pt] (61pt,88.9609pt) rectangle (105pt,120.5703pt);
\node at (68pt,95.9609pt)[below right]{Alice};
\draw[color=plantucolor0000,fill=plantucolor0000,line width=1.0pt] (73pt,67.6094pt) -- (83pt,71.6094pt) -- (73pt,75.6094pt) -- (77pt,71.6094pt) -- cycle;
\draw[color=plantucolor0000,line width=1.0pt] (29.5pt,71.6094pt) -- (79pt,71.6094pt);
\node at (36.5pt,53.6094pt)[below right]{hello};
\end{tikzpicture}
\end{document}
We need now to have some help : if anyone knows how to change the lines:
% should have a box from (8pt,3pt) to (47pt,34.6094pt) that links to http://www.yahoo.com
To some valid Tikz expression, please post here!
Regards,