Why can't Workbench handle a 2MB XML variable from invoke?

I have an SQL query that returns about 2.3 MB XML variable.  That works fine but if I set that variable to be an output variable and invoke the process from Workbench I get an InvocationTargetException from org.apache.axis.message.SOAPFaultBuilder.createFault (see below).  I'm running Workbench ES2 9.5 as a Java plugin in Eclipse Indigo (32-bit) on a Windows 7 64-bit system with 8 GB memory.  The same problem occurs on a Windows XP SP3 system with 4GB memory. 

There are no error messages in server.log at all, just the usual SqlHelper message displaying the SQL statement that was executed.  This appears to be strictly a Workbench phenomenon.  The server seems to be able to merge the data with a PDF just fine also.

Here's my eclipse.ini file settings:

-startup
 plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.100.v20110502
-product
org.eclipse.epp.package.jee.product
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256M
--launcher.defaultAction
openFile
-vmargs
-Dosgi.requiredJavaVersion=1.5
-Xms512m
-Xmx1280m

Here is the stack trace from the invocation error:

ALC-DSC-000-000: com.adobe.idp.dsc.DSCRuntimeException: Internal error.      at   com.adobe.idp.dsc.provider.impl.soap.axis.sdk.SoapAxisDispatcher.throwExceptionHandler(SoapAxisDispatcher.java:211)      at com.adobe.idp.dsc.provider.impl.soap.axis.sdk.SoapAxisDispatcher.doSend(SoapAxisDispatcher.java:129)      at com.adobe.idp.dsc.provider.impl.base.AbstractMessageDispatcher.send(AbstractMessageDispatcher.java:66)      at com.adobe.idp.dsc.clientsdk.ServiceClient.invoke(ServiceClient.java:208)      at com.adobe.workbench.utils.invoke.InvokeWithProgressRunner.invokeServiceOperation(InvokeWithProgressRunner.java:230)      at com.adobe.workbench.utils.invoke.InvokeWithProgressRunner.run(InvokeWithProgressRunner.java:125)      at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException      at org.apache.axis.message.SOAPFaultBuilder.createFault(SOAPFaultBuilder.java:221)      at org.apache.axis.message.SOAPFaultBuilder.endElement(SOAPFaultBuilder.java:128)      at org.apache.axis.encoding.DeserializationContext.endElement(DeserializationContext.java:1087)      at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)      at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanEndElement(Unknown Source)      at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)      at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)      at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)      at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)      at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)      at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)      at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)      at javax.xml.parsers.SAXParser.parse(Unknown Source)      at org.apache.axis.encoding.DeserializationContext.parse(DeserializationContext.java:227)      at org.apache.axis.SOAPPart.getAsSOAPEnvelope(SOAPPart.java:696)      at org.apache.axis.Message.getSOAPEnvelope(Message.java:424)      at org.apache.axis.handlers.soap.MustUnderstandChecker.invoke(MustUnderstandChecker.java:62)      at org.apache.axis.client.AxisClient.invoke(AxisClient.java:206)      at org.apache.axis.client.Call.invokeEngine(Call.java:2765)      at org.apache.axis.client.Call.invoke(Call.java:2748)      at org.apache.axis.client.Call.invoke(Call.java:2424)      at org.apache.axis.client.Call.invoke(Call.java:2347)      at org.apache.axis.client.Call.invoke(Call.java:1804)      at com.adobe.idp.dsc.provider.impl.soap.axis.sdk.SoapAxisDispatcher.doSend(SoapAxisDispatcher.java:127)      ... 5 more