Chocolate Vine not flowering

Our chocolate vine is now a couple of years old, seems quite happy as it is growing and sending out loads of side shoots and spreading through our honeysuckle, but just doesn't seem to flower let alone fruit. Has anyone any tips to help it along?

Thanks

 Never heard of this plant -can we get a photo of your chocolate vine??

I can't even get the seeds to germinate, I'm jealous you have leaves 

I think you need two to get fruit. I don't know why it wouldn't flower though.

I can't even get the seeds to germinate, I'm jealous you have leaves 

I couldn't get the seeds to germinate either. Gave up in the end and bought 2 plants from fleabay. From what I understand the best way is to layer a heathy plant.

They've been on a south west facing wall for 2 years and this year is the first we have had flowers. Mass of flowers actually Theres no fragrance to them though  I too thought they'd smell like chocolate but I couldn't smell it.