So/as long as + will

Hi,

please. What do you think about this sentence?

"I’ll lend you the money so long as you’ll pay me back."

I thought that was an example 1st conditional. So I would say "... so long as you pay me back."

I understand we can use "will" in the "if clause" of the first conditional sentence when we talk about the result of something in the main clause "...we should have captive breeding programmes if it will help save species." or when we want to show that we strongly disapprove of something:

A: "That zookeeper was really annoyed with me."

B: "Well, if you will throw stones at the animals, it's not suprising." (although this one seems a zero conditional to me)

Anyway, the example at the top doesn't seem to be any of these case.

Yet, this sentence is taken out of the Cambridge English Dictionary as an example sentence under the entry "so long as".

Thank you for your thoughts on this and your comments.