Please allow the <variable> element allow "any" schema content just like the "handlers". This would allow the user to store custom metadata for their purposes. This data should be persisted to the database and the API should allow its retrieval just like <action>, <assignment>, and <decision>/<handler>, etc.

We intend on using this to assist with driving the user interface from the work flow engine. One type of meta data we need is the "java type" for the variable.