This paper reports on the development of the Interactive Dynamic Stochastic Synthesizer and describes how its implementation of dynamic stochastic synthesis extends previous implementations, in particular with relation to the GENDYN implementation by Iannis Xenakis. The extensions include elaborations of existing features, parameterization to previously hard-coded attributes, new parametric controls, and interface design to support realtime interaction. In particular, the use of dynamic stochastic synthesis to produce a new class of percussive stochastic synthesis sound gestures is explained.