Hi, GCMartin!

You do not see the environment variables because your LXTerminal does not have enough lines to scroll back. If you issue
Code:
su
set > set.log
wc -l set.log
you will get the number of lines in the log file. I get 8454 lines. You can read the file set.log with an editor.

It is also possible to increase the number of saved lines in the LXTerminal's menu. I made the experience that I had to close my LXTerminal and open a new one after I had changed the number of lines to 10,000. Afterwards I could issue
Code:
su
set
and scroll backwards to the first line.