I have grown incense for at least 15 yrs. I have never gotten any fruit..always had lots of flowers. I was told if I would hand pollenate incense with caerulea pollen, I would get delicious fruit. I never did it, however. I do have several caerulea blooming. Apparently the bees didn't do it either.
I have heard that some people do have fruiting incense vines.

Mine is flowering as well.. But the flowers are Waaaaaaaaay up there on the 'thing that covers the patio' making it imposible to polinate them. I did reach up with a long cutting device I made & snipped off a couple flowers- Used them to polinate other passi's, but so far no luck. I've also pulled some of the vines loose so they hang- When the flowers get within reach I've some caerulea pollen in the fridge I'm going to try. We'll see.

For how long can the pollens keep?

I always direct some of the laterals downward so that I have flowering high and low. This lets me photograph, smell, pollinate, and air layer for cuttings.

Hi Krstofer
High up flowers are easy to pollinate.
Simply put some pollen (as much as you can from several flowers) on the end of your cutting device or a bamboo cane (may both need a little adaptation to get a ^ type end, and give the flowers a bit of a push about. I use this technique with actinia, which for the most part flowers at the top only, putting caerulea pollen on it. Fruit will set easily.
Myles

Dragonking see link below re preserving pollen. Always use fresh if possible.

Here is a link that might be useful: Preserving pollen.