Hi Norberto,
could you start your MWS in debug mode (-d option)? After starting MWS in debug mode, when your first portlet redirects to the second one you should see in console something like this:
invoking authHandler: ntlm
invoking authHandler: httpHeader
invoking authHandler: saml
invoking authHandler: forms
invoking authHandler: basic
Could you provide this logs and few next lines from your console? I wonder which handlers are invoked and what information are log out after handlers?
RGDS,
#webMethods-BPMS#webMethods#MWS-CAF-Task-Engine