axis 1.2 client talking to an axis 1.1 server?

[Stuart Barlow]

Does anyone have experience of an axis 1.2 client talking to an axis 1.1 server?
At the moment I am getting the following error...
java.lang.NoSuchFieldError: RPC
	at 
com.hummingbird.hc.dm.api.DmintsoapSoapBindingStub.<clinit>(DmintsoapSoapBindingStub.java:26)
	at 
com.hummingbird.hc.dm.api.DmSystemSPIServiceLocator.getdmintsoap(DmSystemSPIServiceLocator.java:43)
	at 
com.peopledoc.jura.dmintegration.spi.impl.DmIntSOAPImpl.bindToSoapAPI(DmIntSOAPImpl.java:146)
	at 
com.peopledoc.jura.dmintegration.spi.impl.DmIntSOAPImpl.<init>(DmIntSOAPImpl.java:72)
	at 
com.peopledoc.jura.dmintegration.spi.impl.DmSPIFactory.createDMSystemApiForConnector(DmSPIFactory.java:92)

This is an AXIS 1.1 server using WSDL2Java to generate a client library.
I am then running this client lib in an app server that includes AXIS 1.2
in its environment. Is this exception getting thrown by the client code?
Is there a preferred strategy here?
ta,
Stuart