In the Multiparameter window:
- (1) click the Banks tab,
(2) select the target parameter,
(3) set the Value Mode to use the parameter's values,
(4) give the Multiparameter a suitable name,
(5) set the number of bank values (that is, number of steps),
(6) enter the values for each step,
(7) turn OFF "Interpolate values" (to produce steps rather than continuous change).
>>>> http://i.imgur.com/mXCdX30.pngAnd the result:

