Increasing amount of maximum stuff to use?

Does anyone know if it's possible to increase the amount of stuff that you can use in the scenario creator in RCT2? With all these expansion packs at what not, my selection has greatly increased, and therefore I would like to have more options.

Thanks in advance!

PS - Didn't want to make another thread for this, but is it also possible to create rides while in Scenario designing mode?

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