How to integrate fix points outside of the planned STAR?

[derzierau]

Hello,

two days ago I was enroute to EDDM from the south with the experimental FBW. The STAR to 26L was BETO2B with BETOS26 TRANSITION which consists namely of: BETOS - DM452[R] - DM455 - DM459 - FINAL APPROACH 26L [ILS - LOC - NDB - RNAV(GPS)]

For separation of traffic I was given the directs DM451 thereafter DM459 (DM451 is not part of the TRA therefore not part of the current FP). I tried implement the correct behaviour by using the direct to page which resulted in an falsy looking FP on the ND and an unexpected turn of the aircraft in the wrong direction. Thereafter I decided to flew the aircraft via HDG.

First question: what is the correct way to implement such need into the FMC? Maybe using the Flight Plan Page?
Second one: is the unexpected turn when using DIR to an fix outside of the FP?

Thank you guys!