Yes you can! In the Modeler, when you edit your enumeration, you can sort the values using the 'Move up' and 'Move down' buttons (blue arrows). The values will appear in the dropdown in the order that you specify in the Modeler.
What I usually do is add A - Z before the key. So the Enum looks like:
Caption Key gold aGold silver bSilver bronze cBronze
A little bit dirty. If anyone knows a better solution I would be happy to hear it!
What do you mean with tweak? It is possible to define the order in the modeler.
Enumeration can be found in the resource section of your module. When double clicking on an enumeration you can define the order by clicking on the up/down arrows.
Probably this is not what you mean, but this is the 'normal' way to define the order of a enumeration. Anyway, I hope it is of some use.