Agree with Gail, nice article, plus I'm reading it that you're suggesting that Data Storage for Temp Table is not in memory - for which it is in-memory unless pushed out to disk.
Also, I'm taking it that, as this article is not an old one, that it covers SQL2005. If this is the case, then INSERT...EXEC is supported for Table Variables. You can test this with the following:
DECLARE @helpdb TABLE (name sysname, db_size nvarchar(13), owner sysname, dbid smallint,
created nvarchar(11), status nvarchar(600), compatibility_level tinyint)
INSERT @helpdb (name, db_size, owner, dbid, created, status, compatibility_level)
SELECT * FROM @helpdb