[Zope] password change and cookie crumbler

[Ben Avery]

hi, happy new year everyone!

I'm stuck on a problem involving cookie crumbler authentication:

I'm building a site which requires users to register their own accounts 
and log in. When the users are created, I generate a password for them. 
But I need to allow the users to change their own passwords. At the 
moment I'm using a python script which picks up the new password and 
confirmation from a form, and does this (after checking the new password 
and confirmation match):

------
user = request.AUTHENTICATED_USER
uid=user.getId()

myreq={}
myreq['name']=uid
myreq['password']=request['new_pwd1']
myreq['confirm']=request['new_pwd1']
context.acl_users.manage_users( submit='Change', REQUEST=myreq )

response.redirect( '%s/changed/' % request.URL2 )
return
-------

The code manages to change the password successfully, but I cannot then 
view the confirmation page, and am redirected to CC's login_form page, 
(I think) because the password set in the cookie is now not the same as 
the updated one in the acl_users user folder.

Do you agree that this is the problem here, and if so, what would I have 
to do to fix this?

[Zope 2.6.0, Python 2.1.3, Solaris 7, viewed in Mozilla 1.0.1]

TIA

Ben Avery