[NTG-context] Different formatting of section numbers for title and references.

[Aditya Mahajan]

Hi,
  I want a setup in which section numbers are Roman (I, II, etc.) and 
subsection numbers are Character (A, B, etc. without the section 
number prefixed). This is easy to achieve using

\setupsection[section-3][bodypartconversion=Romannumerals]
\setupsection[section-4][bodypartconversion=Character,
                          previousnumber=no]

However, when I reference these sections, I want
\in[section] to give I (which it does happens) and \in[subsection] to 
give I-A. How can I achieve the correct reference numbering for 
subsections?

Thanks,
Aditya