[NTG-context] Unable to switch math fonts

Hi. I'm using the Debian packaged ConTeXt, version 2017.05.15.20170613-2. I have the Neo Euler OTF font and mtxrun --script fonts finds it. I am unable to get the following to work: \definefontfamily [myfamily] [math] [Neo Euler] \setupbodyfont[myfamily] \starttext This is plain text. \startformula x + y = z \stopformula \stoptext The above code doesn't build for me with errors in the formula portion. However, removing the Neo Euler line makes it work. Moreover, this works: \definefontfamily [myfamily] [serif] [Neo Euler] \setupbodyfont[myfamily] \starttext This is plain text. \startformula x + y = z \stopformula \stoptext But this makes everything, including math, Euler. Could you please help me out? Thanks. Kumar