That's not the problem. The problem is, that the current Percolate license is not a free software license. Non-free licenses are incompatible with the GPL, which flext uses. By distributing a version of Percolate externals using their current license built with GPL-flext you would be violating the GPL! So you are not allowed to distribute your flext-Percolate ATM.
Please pardon my ignorance, but will this be the case even if I distribute the ported code as source-only (assuming that I get a permission to do so from the original authors)? Also, how does this affect Stk+flext, since Stk's license is not GPL either?
Best wishes,
Ico