I want to create custom theme which will use the Lisbon theme as base theme and then I want to use that theme for all of my applications. I am not sure how to do that. I tried this: http://www.outsystems.com/help/servicestudio/9.0/default.htm#Reusing_eSpaces/Create_Your_Own_Application_Template.htm , but it seems like it doesn't work with OS 10.
There is a very nice tutorial that you can follow on the OutsystemsTV page: Build Live Style Guide Training Webinar. It can be a little bit more that you are asking, but will give you a complete overview how everything works.
Hope it helps.