"No, that should be fine, it's just me that's the time travel issue.  I recommend - here."

She sends over a copy of her own notes from when she was trying to figure out how to do this in her idiom.

Well, alright then.

It's a much more delicate operation than the things that it has attempted so far, but after several more orbital cycles P.E.R.C. is able to make a pair of tiny aluminum rings through which light can pass instantaneously. The addition of a second set and a loop of fiber-optic cable completes the mechanism.

The measured delay through the system is on the order of 30 nanoseconds. The rings are physically separated by just over one light-nanosecond on either side. That means that the far end of the relay needs to be traveling at just over 99.9% of the speed of light to get retrocausality. Normally, this would be prohibitively difficult — even with such a light payload, P.E.R.C. would need to spend a long time collecting and refining rocket fuel, due to the tyranny of the rocket equation.

In this case, however, it recently perfected the problem of applying reactionless thrust to nearby objects. And thanks to the aluminum rings, the far side of the ansible connection is always 'close' enough. It's very difficult to accelerate the far side without collapsing the ansibles, but 'very difficult' is just another word for 'possible with sufficiently precise machining, design, and reflexes'.

P.E.R.C. runs final checks. The probe, simple as it is — a hard ablative armor shell around a length of fiberoptic cable and two washers — is functioning correctly. P.E.R.C. applies a strong gravitational acceleration to the device, flinging it up and out of the system on a course toward intergalactic space, through the available corridor with the least dense interstellar medium, to minimize damage from relativistic impacts.

"The probe is away. In 1.4 years it should be traveling fast enough to permit retrocausal signaling."

...If it's just a matter of power, at this point, she could probably give this thing one hell of a kickstart, actually.  She's not planning on doing anything that big in the next hour or so.

Well, power and being able to apply it without destabilizing the communication effect, but yes. It just needs 2.16 exajoules of kinetic energy pumped into it, spread over whatever timeframe seems reasonable.

...She's not capable of quite that much bomb pumping...  Nevermind that that's not the right word it's close enough...

...but, hmm.  Let's see what happens when she turns a collossal mana pool to Trying Anyway.  If she could just...?

The energy equivalent of a small nuke is promptly bound into accelerating the widget directly.  Over a long enough period of time that nothing explodes.