Try the old version of the DSP's which support low bitrate streaming.
Check out the Sticky post titled:
SHOUTcast: Important Info & Answers to FAQs. READ ME!
Scroll down a bit and look for the section titled:
General SHOUTcast Information -> Where can I download the old version of SHOUTcast DSP?
Yes, I know it says DSP
. It also has older DNASs.
Alternatively, check out Sawg Stuff