Psionic Power also contains no rituals. The skill used for a ritual doesn't affect anything mechanically, so you can reflavor rituals as psionic without issue -- I do this for my psion. But yeah, it seems like a bit of a lack.
It's probably worth noting that rituals don't have an associated power source, just associated skills. WotC decided not to add a Psionics skill to parallel Arcana, Religion, or Nature, so I don't think we're likely to see anything specifically psionic. I think Arcana more or less fills in for a psionic skill, which may or may not be satisfying.
Mechanically speaking, it would be reasonable to house rule a Psionics skill that's an exact cognate to the Arcana skill. I'd use Psionics instead of Arcana for monster knowledge checks on aberrant creatures, and substitute it for appropriate rituals.