I should like to have the Brill font substitute for the Greek alphabet (upper and lower cases) as well for the numerals in Tex Gyre Termes Math. 

So far, I have been able to get the Brill numerals (oldstyle) but nothing more: the Greek letters in math mode are from Termes Math.

Here is what I have:

\definefontfamily[mainface][serif][Brill]
[protrusion=quality,
expansion=quality, 
mode=node,
force=yes,
]

\definefallbackfamily[mainface][mm][Brill][range={0030-0039, 0391-03A9, 03B1-03C9}, scale=1]

\definefallbackfamily [mainface] [mm] [Brill] [preset=math:lowercasegreeknormal]
\definefallbackfamily [mainface] [mm] [BrillItalic] [preset=math:lowercasegreekitalic]
\definefallbackfamily [mainface] [mm] [Brill] [preset=math:uppercasegreeknormal]
\definefallbackfamily [mainface] [mm] [BrillItalic] [preset=math:uppercasegreekitalic]


\definefontfamily[mainface][mm][TeX Gyre Termes Math][scale=0.94]
\setupmathematics[autopunctuation={all}, ucgreek=normal, lcgreek=italic]

\setupbodyfont[mainface,10pt]

\starttext

A~B~C~a~b~c

\emph{A~B~C~a~b~c}\quad math: \m{A~B~C~a~b~c}

0123456789\quad math: \m{0123456789}

δ \emph{δ}\quad math: \m{δ}

π \emph{π}\quad math: \m{π}

Π \emph{ Π}\quad math: \m{Π}

\stoptext

Any suggestions or pointers will be most welcome.

Alan