What do you mean by "allow access to the private keys to official wallet"?
It is impossible to export private key in testnet..we can just import key..if wallet crash how can us restor it ?..privat key is an security allowing export fonds..so plan yu to allow this fonctionality in official wallet.
Unlike Bitcoin, private key in Byteball is not enough to restore access to funds. Hence, to avoid giving false sense of security, I removed the export function.