I realise that but there really isn't another way I can go about this.That is still very risky and can lead to instability.
There's GOTTA be a shop or someone near you that can repair a physical volume button.
I think that would be your best solution instead of trying to figure out how to disable such a great feature as safe mode and making your JB and device unstable you should be trying to fix your broken device instead.
That's what I would do.
The reason why I have to do it like I am is because there is one repair shop nearby that makes you pay a ton and more than often you get your device back with another broken button or the screen coming off, not to mention they format your device for (as far as I'm aware) no good reason. I don't have a lot of money to pay for repairs and this way I can use my device and not have to pay more money to get it fixed.