It's always at least a learning experience to try, but "sterile" in this case likely means that both the male and female parts of the flower are incapable of reproduction.

I really don't know much specifically about canna flowers, and sterility. I have learned that on other plants alot of times the reason it doesn't produce seeds is because the pollen(male parts) isn't good, but the female parts are.
Here's hoping!

I believe I may have read an account of this happening with a sterile cultivar but typically it would be very uncommon. It would be an interesting experiment to try but I would combining the pollen from the "sterile" canna with the seed producing canna and visa versa to increase your odds. It would be great if you could get some feedback on this from one of the canna experts on GW like canna2grow.

Generally speaking, a hybrid canna cultivar that does not self-pollinate and produce seed will be unlikely to produce seed by using pollen from any source. There are numerous reasons for seed sterility in the mother canna. The accumulation of deleterious genes from inbreeding may interrupt any of the many critical phases of the reproductive cycle. The ploidy issue is always a concern. Angiospermous plants like cannas require a double fertilization sequence. The sexual cycle includes development of the male (pollen) and the female (embryo sac) structures of the flower. The cycle reduction division of chromosomes must occur to produce the haploid (N) chromosome number. Pollen grains and the embryo sac contain haploid (1N) male and (1N) female gametes. Pollen must transfer to the stigmatic surface (pollination) and germinate. The pollen tube grows down the style into the ovary until it reaches the embryo sac within the ovule. Two male gametes from the pollen tube are discharged into the embryo sac  one to unite with a female gamete (fertilization) to produce the zygote (2N) and another to unite with the two polar nuclei to produce the endosperm (3N).
Failure of the endosperm to develop properly results in retardation or arrest of embryo development. This phenomenon commonly occurs when two genetically different individuals are hybridized, either from different species or from two individuals of different polyploid constitution in angiosperm plants.
Because the seed bearing plant must be capable of performing a multitude of complex tasks to successfully complete the seed development cycle one is "usually" correct in assuming the deficiency is with the potential seed bearer. The pollen from this plant may likely be viable. Trial and error is still needed to confirm any final conclusion.
Regards,
Kent

Thanks, canna2grow
I'll try using the steril cannas pollen on another plant, but this will make it tougher to tell if it worked until the seedling show signs. But definatly worth the effort.