According to the LOWW ILS 29 chart, there are 3 numbers for CAT 2:
1. RA 97'
2. DA 700'
3. DH 100'
All those 3 represent the exact same point on the glideslope. With perfect equipment you could use 700 QNH, 100 QFE, or 97 AGL. But the baralt is not accurate enough for these low minimums, therefore the reference you use is the radalt which happens to be 97 feet at that point on the glideslope. As for what goes into the kit, your aircraft also needs to have the correct reference as determined by the approval process. As for regulation, in the USA at least, you can in theory use an inner marker instead of the radalt - which would be the case if you saw "RA NA" (not authorised), but not in Europe.
My company's manuals quote the words "DH is determined by radio altimeter" only, no mention about RA.
...using the published RA puts you at the DH. That is what it means.