After some much further checking (Take a look at "Mutabilis" by Drew Wager in Google Books), it seems that if FD is going off of the original lore, Raxxla is a Rouge Planet that travels though witch space, stopping at predetermined points along the way (one of which is Lave). The entire cycle completes every "few decades." Raxxla was the hub that kept witchspace operational (The aliens that created Raxxla also created witchspace), but using it as a transit system damaged it over time, which seems to have led to the creation of the Frame-Shift Drive.
Anyway, according to the lore, the only way to find Raxxla was to look for witchspace anomalies (in the form of wormholes) or gravitational anomalies (in the form unusual planetary orbits) in normal systems. Using some basic math based on what direction the orbits are stretched in and how stretched they are, you can then get a rough estimate for the direction and distance that Raxxla is from the star.
Also the following quote may be helpful; It refers to Lave's moon, which was eventually found to be Raxxla before it entered witchspace again:
"Astrometrics failed to pick it up until it was very close in to system space [...] It still doesn't register properly on scanners even now half of the time - "
This implies that even an advanced discovery scanner might not pick up Raxxla unless you are very close to it. With this in mind I would say to check for strange planet orbits, and to then start repeating scans as you get closer to the point that the anomaly is at.
Keep this in mind, and may you find many new discoveries on your journey to Beagle Point, CMDR.