how establish presumably sqlconnection enlisted system.transactions' tx not?

when controlling transation system.transactions (creating transationscope an instance) default sql-connections (system.data.sqlclient.sqlconnection) (but is't also loyal oracle.dataaccess.oracleconnection) enlisted opening.
that's called auto-enlistment. good feature. nonetheless incited off throught tie string's parameter (enlist=false). box tie being uninterrupted wouldn't enlisted.
but enlisted manually later.
so doubt is: given sqlconnection's instance i establish presumably tie enlisted (into an system.transaction).
i feeling during tie twine parameter. nonetheless won't since i conspicuous tie enlisted manually.