[Switch()...case]From String to enum

As may be I have made it more complex than what I wanted at the beginning my
code does not work with this :
        public enum myMenuEnum {
                /* we initialise menu item constants */
                SOSA_SET("Set indexation with..."), SOSA_CHANGE(
                                "Change indexation to..."), SOSA_GET(
                                "Get individual from index..."), SOSA_REMOVE(
                                "Remove all indexes...");

                private String item;

                /* constructor for myMenuEnum */
                myMenuEnum(String item) {
                        this.item = item;
                }

                /* method to retrieve menu string constant value */
                public String getItem() {
                        return item;
                }
        }
When I want to test with a switch structure from a string value called
menuItem with this :

switch (myMenuEnum.valueOf(menuItem)) {

case SOSA_SET:
....
break;
case ...
break;
}
I get the following error message :
No enum const class genj.plugin.sosa.SosaMenuAction$myMenuEnum.Change
indexation to...
So apparently myMenuEnum.valueOf(menuItem) is not the proper variable to set
in switch () to test against SOSA_SET, SOSA_CHANGE, SOSA_GET or
SOSA_REMOVE.

What is wrong here.