Stepping up the temps on a HERMS system is not the same as performing a decoction mash. With decoction, you're drawing off some wort and heating it, which adds some caramelization (sp?) to the taste equation. With HERMS, the recirculating wort never reaches a temp much higher than the mash temp, so theres no caramelization.
You can certainly try to use your HERMS to step through these temperatures, but the beer won't be exactly the same as if you decocted it. That said, it will still be pretty good beer.
Since this is your first time using the new equipment you may have trouble with dialing in your temp. I'd strongly recommend picking a recipe with a single mash temp (say, 153). That way you can learn about how your setup holds temp,and how to tweak it.