Can you mount it on the stem? Quill or threadless? If it's a quill stem, should fit fine. If it's threadless, several folks offer a headset spacer threaded for bell mounting. Like Dimension, Velo Orange, Portland Design Works, maybe others.
I know I'm an old, but I'm just not down with using zip-ties to attach critical stuff.
Having just said that, my Garmin attaches with, basically, hi-tech rubber bands, oversized o-rings. And I was just googling bells, and there seem to be lotsa bells that use o-rings to hold 'em down. So what do I know?
To hopefully redeem myself, have you all seen the silly video where somebody in Japan moves through the streets, and then the aisles of a dep't store/supermarket, holding a detached bell. Wherever he rings it, crowds part. Even inside the supermarket. It's all in Japanese, but the visuals are universally understandable:
Paul Brodek
Hillsdale, NJ USA