GST / RulesItemManager / RulesItemManager2

Hi All,

I am trying to get jbilling setup but running into a few issues.

I am tryng the add gst to orders using the gui via a simple rule and 
using the RulesItemManager plugin or the RulesItemManager2 plugin 
however get varying issues depending on which one I use.

When using the RulesItemManager plugin I get a NPE thrown from the view 
layer as follows:

javax.servlet.ServletException: java.lang.NullPointerException
	org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:545)
	org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:486)

bla bla caused by:

java.lang.NullPointerException
	com.sapienter.jbilling.client.order.NewOrderItemAction.execute(NewOrderItemAction.java:132)
	org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)

When using the RulesItemManager2 plugin, I do not get any exceptions but 
instead of adding 10% tax, a charge of $10 is added to the invoice.

Looking thru the minimal doc and other posts for this kind of issue it 
looks like I most likely have some conflicting plugin configured but 
there is no reference to say "if using a, then only use b and c but no x 
y or z" so I am not sure what needs to be added / removed.

I have version 2.1.1 running on java 1.6.0_20-b02 on Linux. I have a