Just connect a single 1/4 wave wire to the antenna pin.
I prefer to use PTFE wire, looped thru a PCB hole as a strain relief. The PTFE wire is very tough and slipperly and seems to reduce the chance of damage or removal of the wire.
I have done this lots for both 434mhz and 868mhz devices, and whilst it may not be ideal, or could affect certification for the module you are using, it does work.