When using the <io:soap> tag in a JSP file more than once an error occurs the
second time:
java.net.ProtocolException: cannot write to a URLConnection if doOutput=false -
call setDoOutput(true)

The implementation in org.apache.taglibs.io.HttpSoapTag has a constructor which
calls setAction("SOAP"). But the instantiation is done only once per JSP page.
As the URL connection in URLTag, which HttpSoapTag extends, is released after
the first use of <io:soap> the action is reset to the default GET action thus
resulting in the abovementioned error at the second call.

Proposed fix:
Move the setAction() call from instantiation to configureConnection():
diff HttpSoapTag.java.orig HttpSoapTag
51d50
<         setAction( "POST" );
62a62
>         setAction( "POST" );

This seems to work.