Hi Jenny,
The most helpful thing for hemangiosarcoma I have found, esp if there is bleeding is Yunnan Paiyao. http://pathwithpaws.com/blog/2011/06/11/a-magic-vial-of-yunnan-baiyao/
I also usually use artmesinin. The rest varies a lot dog to dog. Hemangio is unfortunately one of the hardest cancers to work with but the yunnan paiyao can be pretty impressive.
best wishes,
Lena