Changing Nero Burn Speed

I am trying to use the Nero BackItUp module in Nero6 Ultra. However, there is no option to modify the burn speed to DVD.
I am using 4x DVD-R media, however my drive is a Pioneer 107D with the modified firmware from the firmware page; therefore Nero happily burns away at 8x, which leads to coasters.
So… How do I force Nero to burn at the speed that I want it to burn at? I know that in other programs, If i set the DVD to burn at 1x or whatever, it will burn at that speed (this is contrary to what people keep saying that it is impossible to set the DVD burn speed with software).

Have you tried to turn of Dynamic write speed?

You can find the link below:

When a disc is inserted, the write speeds available are generated from the disc information. If you turn the dynamic writespeed off, then the write speeds are derived from the firmware and not the disc.