[macsolve]

I got this response from Brookhouse support:

In principle the iMux could be configured for your purpose, but there is only a small number of people who understand and can confidently configure Wifi networks. We have decided to keep it simple and to pre-configure the iMux for an ad-hoc network called Brookhouse_iMux, as a "cable replacement" for communication with an i-device. This suits 95% of users and is to avoid that we have to spend a lot of time on wireless networking support.

This makes iMux in its current form a no-go for me. I asked them to note a feature request to make this configurable.

Also, using iMux with an iPad isolates the iPad from internet completely since it can't use both wifi and 3G at the same time (contrary to my reasoning above).