We just start to usr JBoss BRMS 5.1 to develop some rules but we faced with this bug so we tried to used the 5.2 version. But we faced an new problem. Here is copy of the screen shwoing a rule developed with the 5.1 version and show after change to the version.
As you can see the part the rule which use an Accumulate fonction is inactive (but the rule still valide according the validate function). Indeed, there's no more 'Number' in the dropdown list box. The manual still present the use of Number in Accumulate fonction.