You have to determine when you're in your window to flip. Here is a thread with a CEM60 where they got it to work:
Can you post pictures of your ASCOM settings for your mount? There is a disagreement between when SGP asks for it (the things you set on the telescope tab) and what you have set in ASCOM for your mount. You need to sync up what is displayed on the ASCOM driver (time to pier flip) and what is shown on the bottom tool bar for SGP.
Also, you can practice meridian flips during the day. Make a profile without platesolving and guiding. Slew to a target near the meridian. Wait until you're inside your 'window' for SGP/the mount. From the telescope tab, tell SGP to perform a meridian flip. If it works, you're golden, if it doesn't, you need to adjust either SGP or your mount's settings.