Hi Ellen,
You need to let them be(on the plant) until the outer shell turns crispy. If you try to remove ipomoea species seeds before then, they will end up being moist as you found out and no good.
Remy

oh dear, then I'm out of luck.
lol - I cut off all the seed pods!
oh well, I can trade for them.
Anyway I didn't have very many blooms from them.
You're in my zone, Remy, do they do well for you?

Ellen,
Lol, we've all done things like that! I've not grown the Brazilian MG yet. I've grown a lot of others though, and they are all the same in respect to their seeds. As far as blooms of MG species, some of them take awhile to get going like Ipomoea alba(White Moonflower.) The flowers were spectacular. Unfortunately it took forever to see blooms, and then many of them got lost to frost. Not all are like that though. Some species start pumping out blooms earlier. For the Brazilian MG, I wonder if starting early, potting up and having a good size plant to get in the garden once spring frosts are done would work better.
Remy

ellenr,
I grew Brazilian morning glory for several years and didn't save the seeds, since they came up volunteer from the previous season's seeds. Finally, however, I didn't get any seeds from the previous year to come up. I was using the Brazilian morning glory to graft sweet potatoes for possible cross-pollenation. If you have seeds to spare, please let me know. Thanks. --Taterman

Sorry - no seeds.
good luck finding them.
sounds like an interesting pollination project.