[groff] Getting refer to pass through special Unicode characters

[Dorai Sitaram via groff]

I have some some Unicode characters with codes higher than 256 (e.g., smart 
quotes) that 'refer' chokes on with the message "invalid input character code". 
 
Is there a way to tell refer to just pass them through to stdout? The error 
happens even if the offending characters don't occur inside the refer-specific 
.[ and .] or in the bibliography database. They are just in the "surrounding" 
text that isn't relevant to refer anyway.
ThanksDorai