Roman Lim's fix:
"i noticed that my application (running on tmotes) using dma on spi does not go to the lowest possible sleep mode but only to LPM1.
i managed to find out, that in McusleepC when calculating the lowpower mode, ME1 had the USPIE bit set. this is, because in Msp430SpiDmaP the unconfigure command does nothing. I don't know, if this is done on purpose, but if not, the same code as in Msp430SpiNoDmaP would do the job (see follwing diff)