Soft phone plugin for Spark to work with Openfire

We are looking for some one to develop a softphone as a plugin for Spark IM client. It should have the below features: Phase 1: * Making a Call * Answering Call * Mute/ Unmute * Hold/ unhold * Speaker Phone * Mutiple call handling * 3 way calls * Audio Preferences - Speaker and Mic * Call Transfer * Voice Mail button * NAT and firewall support Also you need to change the UI/Skinning with the images and text provided and develop a executable using Install4J or someother build tool. We can provide you a copy of Install4J build tool, if needed. Phase 2: Integrating codecs requested Requirement: 1) We are only looking for someone who has demonstratable experience working with Spark Plugins and SIP phone development. 2) Should be delivered on time promised. 3) Payment will be made only after successful demo of the working application on our computers. You can give the source once payment has been made. If you are familiar with Spark IM, it already has a plugin called SIP Phone plugin which does exactly same as what I mentioned above and you do not have to do anything but there are some issues with that plugin and that is why we are looking to develop a new plugin. The issues with the SIP phone plugin are: 1) For incoming and outgoing calls audio quality is not good. 2) When continuously Called the spark will Hang up 3) Transfer and Hold Functionality is not working 4) Only ULAW and GSM codecs are available. 5)DTMF is not working properly.