How to BIDS dual-echo pcASL sequence acquiring both CBF (/perf) and BOLD (/func) modalities?

Hello!
In our multi-modal MRI session, we’re running a dual-echo pCASL sequence. This dual-echo sequence allows to acquire BOLD and perfusion data simultaneously (at rest in my case). The issue I’m having is that the BIDS standards puts BOLD fmri data in the /func modality and the ASL data in the /perf modality. I am not sure what’s the correct way to deal with my dual-echo sequence. Where to put this data so it complies with BIDS standards? This case doesn’t seem to be covered in the recent BIDS-ASL extenstion (https://psyarxiv.com/e87y3/).

Any insights from the ASL and/or BIDS experts out there?

Many thanks!
Gabriel