Poison cloud and belt of regeneration?

[warpigdave]

When paying the other day my beast master was down to one life had a belt of regeneration on but was in a poison gas cloud.  Now using the belt first I would heal two-hit points, Then take 2 damage from the poison gas cloud. However if the gas cloud damaged me first I would be dead.  So my question is which do I do first?

We ruled that basically whoever had initiative got their choice of which effect to apply first. However this resulted in my defeat as it was my opponents initiative. Now that I think about it though it seems like they could almost happen simultaneously you regenerate 2 you lose 2. Basically cancel one another out. This to me seems to be fair for both players, basically my belt is negated by he cloud, but I'm not defeated.

[sIKE]

During Upkeep the mage decides how he will process effects such as these, including the order performed.

[Shad0w]

Rulebook V2 PG:7
You always choose the order in which events that affect your creatures and objects occur during this phase. In the rare case that a timing issue occurs, the player with the initiative decides the order.

Example:
You control a Highland Unicorn with the Regenerate 2 trait that has a Burn marker on it. Since the creature has a lot of damage on it, the Burn effect could destroy it. You can choose to resolve the Regenerate trait first,  before the Burn effect.