Is it permissible to substitute an existing debt or loan for the remaining counter-value in a failed exchange transaction?

Primary text

If a person has only five Dirhams and buys half a Dinar with them, receives a full Dinar, pays the Dirhams, and then borrows the Dirhams back from the seller, using those borrowed funds to purchase the remaining half Dinar, this is permissible. Likewise, if he initially exchanges for the full Dinar with ten Dirhams, pays five, then borrows the remaining five Dirhams and gives them as the counter-value for the remaining half, without it being considered a trickery device (hila), there is no objection. Imam Ahmad stated the ruling on these points.