Here is method 1:
YOU file an IFR flight plan. YOU are PIC. Wear foggles in the VMC,
take them off in the clouds. Your safety pilot is safety pilot only
when you are in VMC. You log PIC, he doesn't log anything (he COULD
log second in command if he wants).

Here is method 2:
Your SAFETY files the IFR flight plan. You wear foggles in VMC, take
them off in the clouds. Your safety pilot can log PIC (by virtue of
being in charge of the flight). You log PIC by virtue of manipulating
the controls.

You can't do method 2 because your safety pilot is not IFR rated. But
you CAN do method 1. If you rent the plane you probably don't want to
do method 2 anyway, even if your safety is IFR rated. So do method 1.