[TYPO3] newloginbox + https_enforcer + redirect = problems

[Claudio Strizzolo]

Hi all
I'm trying to make a page containing newloginbox plugin and using the 
https_enforcer extension handle correctly redirection.
Basically, after a successful login, I need to return back automatically 
to the page from where the user came to the login page (let's call it 
"the start page"):

start page ----> click on a link ----> login page ----> automatically 
back to start page if login succeeds

In the start page (uid=100), the link to the login page which includes 
newloginbox is displayed like this (realURL involved too):

http://mysite.com/login.html?redirect_url=index.php%3Fid%3D100

newloginbox should be able to understand redirect_url, I guess by looking 
at the code. In fact, everything works correctly if https_enforcer in the 
login page is turned off: the user logs in and he/she is automatically 
redirected to the start page again.
If I turn https_enforced on for security reasons, however, when the user 
logs in the redirection does not work, and the user remains in the login 
page which displays the usual status and logout button.
I'm puzzled. Any hints?
Thanks in advance

Claudio