There was a thread about this a long time ago and i posted a detailed desription of his equipment, but what you might find most helpful was a post i left with my multi-fx settings to get a texas/blues (stevie ray vaughan) type sound

Here's the thread http://www.guitartricks.com/forum/showthread.php?t=9391&page=1&pp=7

my setting are on page 4 (please ignore my atrocious rendition of Lenny, that was recorded a LONG time ago after i had only been playing for about 2 months)