How to dynamically start a task from a process that was started from an HTML Dialog

Hi all,

In a JSF Dialog we can start a task dynamically with:

FacesContext.getCurrentInstance().getExternalContext().redirect(ivy.html.taskstartref(ivy.wf.findTask(95)));

We can also start an IProcess dynamically with something like that:

IRequest request = requestFactory.createRequest(processStart, thisMapOrEmptyMapIfNull(params)); 
IResponse response = responseFactory.createResponse(); 
IRequestHandler requestHandler = (IRequestHandler)processStart.getProcessModelVersion().getAdapter(IProcessEngine.class); 
requestHandler.handleRequest(request, response);

Now we would like to combine both to start a process dynamically that should in turn start a task. The process can be started from within the JSF Dialog.
In the started process, as we are not in the JSF context, the following does not work (fails silently):

FacesContext.getCurrentInstance().getExternalContext().redirect(ivy.html.taskstartref(ivy.wf.findTask(95)));

The following code does not work as well (fails silently):

IHttpResponse resp = ivy.response as IHttpResponse;
resp.sendRedirect(ivy.html.taskstartref(in.task));

We tried also:

IHttpResponse resp = ivy.response as IHttpResponse;
HttpServletResponse sresp = resp.getHttpServletResponse();
sresp.setStatus(HttpServletResponse.SC_MOVED_PERMANENTLY);
sresp.setHeader("Location",ivy.html.taskstartref(in.task));
sresp.sendRedirect(ivy.html.taskstartref(in.task));
sresp.flushBuffer();

Here we get:
IllegalStateException: Cannot change buffer size after data has been written
Cannot set content type. Response already committed

Is there a possibility to achieve what we try to do? Like for the process-start I have tried to find a proper IRequestHandler for starting a task. I have not found it.

Thanks a lot in advance

Emmanuel