The computational platform ENVIRONMENT, developed to simulate stochastically reaction systems in varying compartmentalized conditions [Mavelli and Ruiz-Mirazo: Philos Trans R Soc Lond B Biol Sci 362:1789-1802, 2007; Physical Biology 7(3): 036002, 2010], is here applied to study the dynamic properties and stability of model protocells that start producing their own lipid molecules (e.g., phospholipids), which get inserted in previously self-assembled vesicles, made of precursor amphiphiles (e.g., fatty acids). Attention is mainly focused on the changes that this may provoke in the permeability of the compartment, as well as in its eventual osmotic robustness.