Thanks.php: Echo back the username and password?

Hi

I've had a good look and tried a few things suggested in the help/docs and forums but without success.

How do I echo back the username and password in thanks.php.

I want to say something like:

Thanks, Fred Bloggs. Please make a note of your login details:
Login username = fred123
Login password = dogsname​

I tried adding the following test code to thanks.html:

print "Welcome, " . $_SESSION['_amember_user']['name_f'] . " " . $_SESSION['_amember_user']['name_l'];

But I just see "Welcome, " and no user data.

I can't rely on the user remembering what they just typed 2 minutes ago, and they won't have email access to receive confirmation, hence the need to echo it back immediately.

Cheers
Russell
aMember newbie