Hi @Leif Penning,
I am sorry to hear that didn’t quite work for you!
At the moment, however, there isn’t a documented, dedicated placeholder that lets you pull in the Custom message field directly into a fully custom HTML confirmation template in the same way as those standard placeholders.
Right now, the supported use of Custom message is to add a one‑off, per‑reservation message from the Mailing tab when sending/creating the confirmation email, rather than via an HTML placeholder inside the template itself.
I completely understand the value of what you’re trying to achieve, especially if you’d like to continue using your own HTML design. I’ll pass this feedback along to our development team to help spark further discussion on the feature.
I remain at your disposal.
Best regards,