That's probably a good thing to do, but did you take a look at the overall performances of the filer ? Did you consider that you might not be saturating the 1G link(s?).
Basically, the filer with have more bandwidth to handle connexions from the 1GB clients, that's quite straightforward.
A couple of other things to consider:
The 2240 has limited expansion, a single slot per controller. It's a choice of either a dual-port 10GbE or 8Gb FC mezzanine card.
You've 4 x 1Gb ethernet ports per head, bonding them together using LACP or similar might be a more cost effective solution.