Options for impersonating users via REST with non-ASCII usernames?

Hi all,

I've been working with the API for years now and normally I have no issues with impersonation by adding a header like this.

Rest-Impersonate-User: robert.hanson

I have also used with with non-ASCII characters, including non-latin and asian character sets.

Technically using non-ASCII in the HTTP header is illegal per the specification (from my research), although it normally works with Verint.  In my case the deployment has some hardware/software in front of the Verint instance that might not be allowing the technically malformed header to pass.

My question is, is there a HTTP valid way to do this?  Like, will URL encoding of the username work (it didn't appear to)?  Or is it possible to use the user ID instead?

Thanks.