Dear Khaled,
PreComp and VABS are sectional analysis tools that are used to derive equivalent beam properties of a cross section (6x6 sectional mass and stiffness matrices) based on the shape and composite layup of the cross section. A beam-analysis tool, such as BeamDyn, coupled within an aero-elastic tool is still needed to run load cases and calculate response over a range of conditions.
Regarding FAST, similar questions have been asked on the forum: FAST Blade Structure: Isotropic vs. Anisotropic material. Again, the arrival of BeamDyn will greatly expand the capability of FAST to analyze large flexible composite blades.
Best regards,