Definition of new address format for Segwit address

[azuchi]

Bitcoin introduced the new address format Bech32 used by Segwit.

Addresses such as P2PKH and P2SH are consists of address version, payload and checksum, and Open Assets Address has namespace added to it. But Bech32's address format has no version, it consists of human-readable part, separator and data part(include checksum).

If I want to convert from Bech32 address to Open Assets Address, should Base-58 encoding be applied by using human-readable part instead of version?

Or should we define a new Bech32 based address using the namespace for OA in Bech 32's Humarn-readable part?

Are there any other good idea?