Messaggio di Nulgar
I'm sorry, I misunderstood what you meant, I thought of the level 90 BoA shaman items from the Timeless Isle, but you meant the Heirloom set
The Elements...
As that page suggests,
Fascione degli Elementi was the intended belt for that set, but it is no longer obtainable. You may find it on the AH, but even then, it's probably gonna have a hefty price tag. However, you can also purchase
Fascione degli Elementi - Replica at the Darkmoon Faire for 55
Biglietto Premio di Lunacupas which has an identical look.
If you don't like that belt, check out
this list of Mail belt items, or get the addon
MogIt, which lets you browse a similar list ingame, with the option to add the other items as well, to preview them on your character directly.
In case you are wearing the Heirloom set while levelling, note that you can also transmog these items to a different look - e.g. the
level 30-60 quest reward sets introduced in Cataclysm. However, despite the Heirloom saying they're Leather below level 40, they are always considered Mail, so you cannot transmog them at all before 40, as you need to be
able to equip the item you're copying the look off.