Patrick, from what I know, temporary tables are just that - temporary. You can insert into them, but as soon as the stored procedure session ends, the contents are gone. An update would work only within the context of the stored procedure.
Is the insert you show above performed in SQL console or within a procedure?
If you performed a SELECT on this table in a SQL console window, do you get results?
I have used temp tables (table variables) in stored procedures without defining them beforehand, ie var_table = SELECT * FROM <table>, and then used in further processing. Not sure if what you are trying to do is something totally different.
Regards,
Justin