Sip Phone/Asterisk Plugin DTMF

I’d like to use Spark as an IM/SIP client, but I’ve noticed that the SIP Phone plugin doesn’t send DTMF when a call is in progress – so it isn’t possible to access voicemail, or any IVR system.

Are there any workarounds, or any plans to add this functionality to the SIP Phone plugin if it doesn’t exist? I’ve noticed that this also holds true for the SIP client in Red5 Sparkweb.

Does anyone know if the Asterisk plugin is affected by the same limitation?

Thanks!

Red5phone sends and works fine with DTMF tones for me in the UK. I am aware of someone who had problems in the US and modified the mjSip client to use SIP INFO messages instead.