3rd Party Call Control - Holding a call via Manager API

It would appear based on this:


And through testing, that there is no way to hold a phone via 3rd party call control/Manager API. The only way to obtain this feature, is by having a phone that supports hold via SIP/IAX2.

Is there anyway around this? So that one may develop a true 3rd party call control mechanism without embedding a full SIP/IAX2 softphone in their 3rd party client?