Why uses Context 8r encoding used instead of the specified ec encoding?

[Stefan Wachter <Stefan.Wachter@gmx.de>]

Hi all!

Fonts are driving my crazy! I have the following document that clearly 
states that the font encoding should be "ec". Yet, somewhere behind the 
scenes the ec-encoded font uhvr8t is mapped into the 8r-encoded font 
uhvr8r.

Can someone reveal this deep secret?

Best regards,
--Stefan

PS: The pdfmapline instruction cause the uhvr8r font not to be embedded. 
Doing so proves that Context really uses the uhvr8r font and not the 
uhvr8t font.

\enableregime[il1]
\setupencoding[default=ec]
\setupoutput[pdftex]
\usetypescriptfile[pdf-typescript.tex]
\usetypescript[pdf]
\setupbodyfont[MyHelvetica,sans,20pt]
\setupheadertexts[]
\pdfoptionpdfminorversion 4
\starttext
\pdfmapline{=uhvr8r Helvetica "TeXBase1Encoding ReEncodeFont" <8r.enc}
This is a test.
\stoptext

With the typescriptfile pdf-typescript.tex:

\starttypescript [sans] [xhelvetica] [name]
  \writestatus{x}{y}
  \definefontsynonym [Sans]            [uhvr8t]  [encoding=ec]
  \definefontsynonym [SansBold]        [uhvb8t]  [encoding=ec]
  \definefontsynonym [SansItalic]      [uhvro8t] [encoding=ec]
  \definefontsynonym [SansSlanted]     [uhvro8t] [encoding=ec]
  \definefontsynonym [SansBoldItalic]  [uhvbo8t] [encoding=ec]
  \definefontsynonym [SansBoldSlanted] [uhvbo8t] [encoding=ec]
  \definefontsynonym [SansCaps]        [uhvr8t]  [encoding=ec]
\stoptypescript

\starttypescript [pdf]
  \definetypeface [MyHelvetica] [ss] [sans] [xhelvetica] [default] 
[encoding=ec]
\stoptypescript