As Tester101 mentioned, in this application there is close to no load on the rim joist, since your actual joists are supported by the beam. Nailing through the rim joist into the end of the other joists will be fine. I've built plenty of decks like this.
Here's a study that was done on end nailing, and the relevant recommendations:
Nails driven into the end grain of wood do resist both static
and impact loads. However, additional research is required
in several areas. Of the 4,723 data points on the relationship
of specific gravity to nail withdrawal strength, only 294 data
points were from tests of nails with a diameter larger than
2.52 mm (0.099 in.). Therefore, research is needed on endgrain
withdrawal capacity of nails with a diameter greater
than 4.1 mm (0.163 mm) so that Equation (5) can be further
Furthermore, none of the studies evaluated repetitive loading
of nails from the end grain since joints in service typically
do not experience strictly static or impact loading. Repetitive
loading may cause end-grain withdrawal capacity to significantly
decrease over time.
There is conflicting data on how threaded nails perform in
comparison with smooth shank nails when withdrawn from
the end grain. Three studies showed an increase in nail
withdrawal capacity whereas one study showed a decrease.
Since the use of threaded fasteners in construction is increasing,
more research is needed to determine the effects of
surface characteristics on end-grain withdrawal.
Finally, more research is needed to determine the long-term
withdrawal strength of nails driven into end and side grain.
The data in this report suggest that over time end-grain and
side-grain withdrawal capacity may become equivalent.
Very few test replicates measuring the effect of time delay
on withdrawal strength were conducted, and more tests need
to be run to clarify these limited observations.
If you still feel like you need more support, yes, you can find something like this:
at most hardware stores. If you're working with pressure treated lumber remember you will need galvanized plates and connectors.