ISR effects in lepton colissions

Dear Madgraph experts,

I am trying to simulate e+ e- collisions with ISR effects, to do so I am considering the following script:

*****
generate e+ e- > vl vl~ e+ e-
output
launch
set pdlabel isronlyll
set lpp1 -3
set lpp1 3
set nevents 1000
set ebeam1 1500
set ebeam2 1500
*****

However, I get the following error:

*****
INFO: Remember that Parton-Shower are not yet ready for such proton component definition (HW implementation in progress).
INFO: Update the dependent parameter of the param_card.dat
WARNING: Failed to update dependent parameter. This might create trouble for external program (like MadSpin/shower/...)
Command "generate_events run_01" interrupted with error:
InvalidRunCard : Assymetric beam pdf not supported for e e collision with ISR/bemstralung option
INFO:
quit
INFO:
Generation failed (no results.dat file found)
*****

I am using Madgraph 3.5.0. and I don't see the problem, especially because I am following the proposed solution to question 706433.

I hope you can help me with this issue.

Thanks in advance,
Paulo Areyuna C.