Don´t find the option to add a MEMO/TAG when send a counterparty token

I need to find a way to add a MEMO or TAG to a payment (esp. for Bitcrystals BCY), cause some exchanges need it to route payments into the right accounts.

Is there a syntax to add it on the receiving address or is there a wallet that has an extension to type in a message? (Casa Tookan and Book of Orbs do seem not to support this.)

May someone help me?
matzci and support sends with memos.