wierd problems running ISP with MP.11's HELP

We've been running a small ISP for over a year using Raylink
Equipment.

We've expanded to a new area and would like to try the Proxim Tsunami
MP.11
equipment. So far, bridging from point to point works well, but we
cannot get the access points to work consistently.

If someone is using the MP.11's in a large network, I'd like to know
what else they are using for hardware to make it work.

We are running MP.11a from our office to our tower (#1). We are
pulling a full T1 at the tower. From the tower, we bridge using
MP.11's 8 miles to another tower using a 24db grid (base unit to
subscriber unit). We are pulling a full T1 at this tower (#2). We then
bridge 21 miles to tower #3 also with an amped 24db grid on each
end(base unit to subscriber unti). We are pulling a full T1 at tower
#3. OK, so far so good. We then put MP11 base units at tower #2 and #3
in order to sell internet from them. We have a 15db omni at each
tower. No dice. From a subscriber unit, we can connect to the access
point, and ping the snot out of it, but no internet. If I try and ping
any other radio besides the access point radio, I loose a lot of
packets and the signal is unusable.
We have a 10/100 switch at the bottom of each tower that all the
radios are plugged in to.

Get this: I put a laptop running IIS with a speed tester at the bottom
of tower#3. I go out and and do a speedtest back to the laptop from a
few miles out using a cheap 12db antenna. I pull over 3mb! I do the
same thing at tower #2 with the same results; great link to laptop but
no link back to my T1. If I plug into the switch at the bottom of the
tower, I get a full T1.

Last thing: once in a while, it will work, but it is spurratic.

Whats up?