There's a couple of different ways, depending on what look you want. I don't know about the Schulz method you're referring to, but I do make bamboo flyrods, so I've done it a bit. If you want a blonde finish color, you can either use an oven, 15 minutes @ 325*, or use a propane handheld torch and flame the inside (pith side), then take a wire brush and brush away the ash from the pith. The method is better described here
http://www.bamboorodmaking.com/html/blonde_flamed_cane.html Outside flaming follows a similar procedure, but you only flame until a nice, deep chocolate color develops. If this method is used, be sure to plane away the pith before gluing up. A light sanding or scraping of the enamel will get rid of the enamel ash and leave a nice, mottled color.
Hope this helps. It works great while rodmaking, but I've never made a bow, so be prepared to experiment a bit. Heat treating bamboo is primarily used to reduce moisture and make the bamboo a little "quicker".
Kevin