Hey Reza I've been doing this with a Palmer PDI-03 for a long time with great results.
I also use Logic and there are better alternatives for loading ir's.
The first is a free plugin called LAConvolver:
http://audio.lernvall.com/
The second one costs 50$ but it's amazing because it gives you the possibility of mixing different IR's and it's called MixIr 2:
http://www.redwirez.com/mixir2.jsp
I have to admit that, IR's are great, but at the moment they are, IMHO, not the "best" way for replacing a real cab.
Let's put in this way. An Impulse Response is like a snapshot, a photograph of a cab in an exact moment.
It's an EQ curve of a speaker in a precise moment.
That's cool and for most of the applications it's perfect.
However with double or quad tracked guitars I've started to have problems because some frequencies started to ring creating some harsh and hollow dissonances.
In recent years a new software was introduced, called Nebula.
It's used for "multi-sampling" different hardwares. From EQ to preamps, from tape recorders to mixing consoles.
And a couple of companies are offering Guitar cabs in this format.
IMO I found amazing the cabs offered by Ownhammer:
http://www.ownhammer.com/
What is the difference between IR and Nebula cabs?
Like I said an IR is "static" instead the Nebula programs are taken with various input gain. So the speaker, like a real one, respond differently based on how much signal you feeding into it, with speaker breakup, ecc.
There was a really cool "shootout" between an IR, a Nebula cab and a real Cab that was really fantastic.
To have a listen you can check it out here:
http://www.ultimatemetal.com/forum/back ... -test.html
Hope this helps