JBRMS does not support business rules with non ascii characters

A very simple rule containing some Latin1 characters (e.g. 'é', 'à'..), is not compiled correctly when using the JBRMS web app.
The exact same rule defined in a DRL file, and compiled with the drools compiler API is well handled (no characters mismatch).
Actually, the rule defined both ways is :

rule "latin_message"
when
Let information message
then
information message containing latin characters léger problème à résoudre hôpital
end

I strongly suspect a poor character encoding scheme inside the JBRMS code, but I haven't been able to identify it.
The problem is illustrated by the LatinMessageTest test case, bundled inside the small eclipse project provided.
It has two test methods, one building the rule using the drools compiler API, and the other using a binary package built with JBRMS.
The second one fails as of the poor character encoding suspected inside JBRMS web app.

Any help is appreciated.