Writing markup into the margins

[Paul Hodges]

I have been asked to place tempo equations (Gould pp185-6) so that the = sign is over a bar line.  If the tempo change is at a line break, this requires half of the equation to jut out into the margin (I've been asked to do that even at the start of a line - pace Gould).  This may be bad practice, but I'm not the editor...

However, I can't make this happen, at least with markup; any attempt to force it just results in the anchor for the markup being moved to bring the markup back out of the margin.

Can anyone suggest how I can get around this?

Thanks,

Paul