Two options. First is to change the sockets for dual-filament bulbs. The running lights will run at 5W, not very bright.
Preferred option, use a trailer light module, running single filament bulbs. Either change the relay to keep the blink rate normal or add two 6.8 ohm, 25 W power resistors in parallel on each bulb.
For either option, use the brown/black wire wire that has a loose connector in the front for the running light power. That is what it is used for on all non-US models.