Carlos,
That's one of my favorite recipes for meatloaf. I smoke it without a pan, just form a sort of loaf shape. I use a Grill-O-Sheet, put the loaf on it, then carefully put it in the smoker. It's a little messy, because all the grease drips off, but it's worth it. I get the Grill-O-Sheets at my local Lowes, but they're also easy to find online. The nice thing about them is you can trim them to the size you want with a pair of scissors, and they're pretty inexpensive, so can be disposable, though I tend to reuse them as much as possible.