TDM over ptp450i

Hello folks, 

I cannot afford  a se t of 650+Idus etc to run 4 E1 over a 80 km wireless link , so I was wondering if any one could guide me on this....Can I connect an IPMux pseudowire box from Rad at each end of a ptp450i link?

i know Rad is not cambium but it is possible to get some Rad boxes from ebay for less than 800 and 450i radios seem to be really great for therir price too.

Any help would be appreciated before throwing away my piggy bank.