Proguard won't keep a class member's enums

I'm working on a library that is distributed as a java jar, and I'm running proguard on it in such a way as to only leave the required interfaces exposed. I have a configuration class with a bunch of member variables and some enum defines. My proguard script preserves the member variables fine, however, the enum definitions are being obfuscated. I've tried everything I can think of to force proguard to retain these internally defined and public enums, but I can't get it to work.

Right now I'm using:

-keep public class com.stuff.MyConfigObject {
    public *;
}

-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

If I try:

-keep public enum com.stuff.MyConfigObject.MyEnum

I get an ambiguous error: "Note: the configuration refers to the unknown class 'com.stuff.MyConfigObject.MyEnum'"

Thanks for the help!