Thank you otb. I have actually tried varexo_det, it did not return the irfs though.
I included varexo_det after varexo in the mod-file (as described in the manual), so:
…
varexo a m e;
varexo_det i;
…
and declared the shock as in the deterministic case and just used ‘stoch_sim’ at the end. The Corr Auto corr blocks were all filled with NaNs.