upgradation from bw3.5 to bi7.3

Hi All,

We have to move our existing system from oracle9.2.0.8,solaris5.8,BW 3.5 TO oracle11.2,solaris 10 and BI7.3.Is it possible to move the upgradation and mIgration from BW3.5 to BI 7.3 or should i move from BW3.5 TO BI7 and Then BW7.3.

And kindly provide me guides and links on how to proceed on this upgradation.

Regards

Ram