If you do the pastry will be horrible. But if you are using a tinned pudding the pastry is vile anyway! You get a similar result to if you microwave any pastry. Soggy and flabby. allow the extra 40 mins and steam. It is worth the effort. XX
i've never done so myself, but to be honest i wouldn't think it would make a huge difference to a suet pudding. it tends to be a bit soft and flabby anyway doesn't it? i microwave my christmas puddings these days and they come out perfect ,although i know that's not quite the same. i'd refer to your microwave book and cook it as you would a sponge cake - not very long.