the problem is neither jmeter or webseal but how badboy was exporting the request in jmeter. The implementation fo the http request need to be httpclient4 in order for the login to work but badboy was settin git to java by default.
And the path saved by badboy is plain wrong, it giving the sub path were has the initial request (which was working) was a level higher.
working: /parent_path/Apps/servlet
badboy: /Apps/servlet
however this seem to not be a problem in a environement without webseal.