The DfuSe protocol made by ST and used in the DSO Nano is considerably different from the USB standard DFU. There is no compatibilty either way. DfuSe uses special DFU files with a number of images including the starting addresses. The host program has to decrypt the DFU file and program the flash at the right memory location after erasing the affected memory pages.
On standard DFU, the host program just sends the whole file to the device and the device knows itself where and how to flash it.
I have been looking at extending the dfu-util program to deal with DfuSe. My non-functional WIP is on http://gitorious.org/~tormod/unofficial-clones/dfuse-dfu-util/commits/dfuse. I have got uploading to work, and am working on setting address pointers. To do is erasing and downloading, and finally, decoding of DFU files.