How to draw a slur above beamed notes with their stems up.

[Robert Blackstone]

Dear all,
In some passages like the one shown in the ME the composer (long dead) wants a 
slur positioned above the beam.

%%%%%%%%%%%%

{\clef "treble" \key b \minor \time 3/8
\stemUp <g' e''>8  ( [ g''8 ) \slurUp  <d'' b''>8 ] | % 137
\stemUp <g' e''>8  \( [ g''8 \) \phrasingSlurUp  <d'' b''>8 ] | % 137
}
%%%%%%%%%%%%

As one can see, the usual tools don't work here and I have not been able to 
find something that does work.

Can anyone help me?

Thanks in advance. 

Best regards, 
Robert Blackstone