Copyright 2013 Robert Clark
CNES, ASI Favor Solid-Rocket Design For Ariane 6.
By Amy Svitak
Source: Aviation Week & Space Technology
October 15, 2010
However, one of the other options discussed for the Ariane 6 would also allow manned European flight capability. This would be the two Vulcain core version.
To estimate the payload capability for the twin Vulcain core I'll use John Schillings launch performance calculator:
Launch Vehicle Performance Calculator.
In the calculations for this multi-Vulcain Ariane core stage, I used this page for the specifications on the Ariane: