My guess is you need to add http proxy properties (assuming the tag used to call the web service is using Axis) before making the web service call.
Here is an example on how to add properties to a given gel script's context system scope variable.
<?xml version="1.0" encoding="UTF-8"?>
<gel:script
xmlns:core="jelly:core"
xmlns:gel="jelly:com.niku.union.gel.GELTagLibrary"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>
<core:set var="newline" value='${systemScope.getProperty("line.separator");}' />
<gel:log>Dump systemScope Variable</gel:log>
<gel:log>Before Adding Proxy Properties
${context.getVariable('systemScope')}<!-- ${context.getVariable('systemScope').toString().replace(',', newline)} -->
</gel:log>
<core:expr value='${context.getVariable("systemScope").setProperty("http.proxySet", "true")}' />
<core:expr value='${context.getVariable("systemScope").setProperty("http.proxyHost", "the.proxy.com")}' />
<core:expr value='${context.getVariable("systemScope").setProperty("http.proxyPort", "8080")}' />
<gel:log>After Adding Proxy Properties
${context.getVariable('systemScope')}<!-- ${context.getVariable('systemScope').toString().replace(',', newline)} -->
</gel:log>
</gel:script>
V/r,
Gene