Hadn't even heard of this one, which always intrigues me, so I hauled out the 'begonia bible', the Thompson Begonia book, and looked it up. Not a lot of information there, and it's often the best source. It was discovered in Bolivia in 1890, it's a low-growing tuberous type, and it is fragrant and has been used in hybridizing to try to get fragrant plants. One, named 'Wild Rose', is a fragrant tuberous one, and another, 'Elsie M. Frey', is fragrant and trailing-scandent. They give three categories of culture, 'for the beginner', 'advanced grower', and 'for the collector'. B. baumanni is 'for the collector.' I think that sometimes means it's difficult, but sometimes means it's the kind of plant that appeals to the begonia addict (like me!) and from your name perhaps you. The only picture is of a print from the year after it was discovered, and it looks quite charming. Probably hard to find, tho' you might have better luck over there. Hope that's some small help.