I can understand your frustration with the support aspect of the site as I too have posted what I thought were general questions and received no response, however the system is free and is produced by a commercial organisation whos focus is obviously on the development aspects.
In general the product is still a beta version and hence support is through the community of users, documentation could be better but to be honest I have found the user interface to be very intutive and therefore the lack of documentation is not generaly an issue.
Have a play and experiment with Pluto and I am sure you will find it to be a great product which can only improve over time.
In terms of your question just use the mouse or remote while watching a video and you can FF, RW etc using the onscreen display, if LIRC is configured correctly then you can use the standard buttons on a remote to achieve such functions
If you are using the UI2 version of the interface then I would recommend switching to UI1 via the webamdnin function as it is much more user friendly when first starting out