DirectLink

Hello,
 
I've a page which contains an image map and each area has associated an
action, in fact a direct action.
 
The  implementation is:
 
HTML
<span jwcid="hiddenZone">
<a jwcid="link">link</a>
</span>
<img jwcid="bottomImage" src="/images/bottom.jpeg" border=0
usemap="#buttons" width="426" height="258"/>
 
<map name="buttons">
  <area shape="rect" coords="324,124,371,204"
href="calculator?service=direct&context=Home/link&sp=Sclear"
alt="Clear"/>
  <area shape="rect" coords="262,124,308,203"
href="calculator?service=direct&context=Home/link&sp=Splus" alt="Plus"/>
  <area shape="rect" coords="325,79,370,112"
href="calculator?service=direct&context=Home/link&sp=Snegate"
alt="Negate"/>
  <area shape="rect" coords="324,33,368,67"
href="calculator?service=direct&context=Home/link&sp=Sdivide"
alt="Divide"/>
  <area shape="rect" coords="262,77,308,112"
href="calculator?service=direct&context=Home/link&sp=Sminus"
alt="Subtract"/>
  <area shape="rect" coords="261,34,308,66"
href="calculator?service=direct&context=Home/link&sp=Stimes"
alt="Times"/>
  <area shape="rect" coords="192,171,250,204"
href="calculator?service=direct&context=Home/link&sp=Sequals"
alt="Equals"/>
  <area shape="rect" coords="132,170,179,205"
href="calculator?service=direct&context=Home/link&sp=Spoint"
alt="Point"/>
</map>
 
Page
    <component id="hiddenZone" type="Conditional"/>
    <component id="link" type="DirectLink">
        <binding name="listener" expression='listeners.processButton'/>
    </component>
    <component id="bottomImage" type="Image">
        <binding name="image" expression='assets.bottomImage'/>
    </component>
    <context-asset name="bottomImage" path="/images/bottom.jpeg"/>
 
I had to  declare a DirectLink even though it's invisible and I encoded
the URL for each area by hand. From my point of view this is ugly and
depends on Tapestry internals.
We've a menu implemented with javascript and used the same technique to
solve this.
My concern is why the DirectLink is just for html links? - Yes, I know
this is a silly question; I guess these cases probably are exceptions
for many applications, however I'm wondering if there is a general
method to deal with direct actions?
 
Is there a better way to encode the href elements?
 
 
Regards
 
David