Blow through.
This is, apparently, how it's done. It places additional stress on gaskets, & some carbs will handle it better than others. I'm personally not a fan of this method, but there are plenty who are & who seem to have some success.

Vacuum Devices
The brake booster should have a one way valve in the line preventing boost from reaching the diaphragm. In order to apply the brake, you must take your foot from the throttle, which closes the throttle & produced manifold vacuum, so there should not be a problem here

Vacuum advance. If the boost is moderately low, then leave it connected. It only comes into play when you have some manifold vacuum in cruise mode, which is the only time that you want it to kick in anyway, & it is in the zero advance position when on boost. The only problem might be with higher boost pushing the hose off the fitting or perhaps damaging the diaphragm.

With some luck, some others will kick in with their personal experiences.

EDIT
Demojob, you got in while I was writing, so you must type faster than me. Good job.