Adding new contrasts in FSL 1st level analysis without re-running model estimation

Dear experts,

I am using FSL for my task-fMRI dataset. I would like to add some new contrasts at single-run level. I wonder whether there is a way to do it without re-running the entire model estimation, which would takes an eternity.
I found an relatively thread on the fsl mailing list (2007) saying that there would be a “edit contrasts” button on the feat post-stats tab. However, I did not see it and suspect that that button does not exist in my fsl version (6.0.0).

Does anyone know whether there is a way to do it?

Thank you so much,

Dear Yuan-hao,

I am confronted with this very issue at the moment. I am thus wondering if you managed to figure it out, and if so, whether you could please advise me on this?

I have two new contrasts I want to generate at single-run level with all model estimates already generated previously.

Hoping you could help!