I need to send JSON objects as strings via packOSC.
It seem sthat the '{' character is not allowed to be entered into a message.
P.s: Jsom looks like this:

{'key':'value', 'string':'foo', 'array':[.0,.0,.75,.3], }

Two objects, [json-encode] and [json-decode], have been released today on the Pd List. Have a look, I'm afraid they have to be compiled before use (which is kind of tough for me).

http://lists.puredata.info/pipermail/pd-announce/2011-09/001945.html