[NTG-context] resetting local footnote number (conversion = character)

Yet another try. I have some local footnotes (conversion = character) and would like to reset set the counter (a) to “a” and (b) to a specific value other than “a”. How can I do this? re (a) \resetnumber[localfootnote] does not work. ! Missing \endcsname inserted. <to be read again> \numberlocalfootnotenumber \setcounter #1#2->\@EA \xdef \csname #1 \endcsname {\the \numexpr #2\relax } l.217 \resetnumber[localfootnote] Am I even right to assume that there is a pre-defined localfootnote counter? Alan