Least Difference and MIMU

Take the ten digits from zero to nine. Arrange them in
two numbers. Subtract the smaller number from the larger one to get the
least possible difference.

Consider the following four rules:
 You can add 'I' at the end of a string ending with 'U'
 If you have a string Mx you can write the string Mxx
 Whenever you find a 'III' you can turn it into 'U'
 Whenever you find a 'UU' you can remove it from the string
Are you able to turn MI into MU?
Source: 1. NPR puzzle for July 16, 1995., 2. rec.puzzles Nov. 21, 1996.
Solution
Mail to Ken