When a formula calls specifically for the use of "diastatic" malt, the point is to get the possible benefits of the amylase enzyme provided by the malt.  Non-diastatic malt has had its enzymes deactivated, and would merely function as a sweetener.

Most recipes designed for use with North American flours don't require malt for a dough that only ferments a few hours, since the amylase levels are adjusted at the mill using malt, or with amylase derived from a fungal source.  If a dough requires a particularly long fermentation (like pannetone), then supplementing with additional malt in tiny quantitites can help ensure that there will be sufficient fermentable sugars remaining after the one- or two-day fermentation has elapsed.

I can't give you a precise equivalency for substituting one for the other.  Usually the amount called for is quite small.  I'd probably just do an even exchange the first time and see what happens.

Wish I could be more specific about what to do.  Good luck.

--Dan DiMuzio

Once again thanks Dan....I have used the malt in some breads that i have made from Hammelman's book....I will try some and see what happens...

Thanks