Mounting an SMB share inside a sysbox container

I'm tasked with giving our DevOps agents (which use sysbox so they can do "Docker IN Docker") access to our Windows network share, and I've got some issues.

a) I cannot mount the share from inside the container, as Docker itself doesn't permit that (would need to add --privileged but that seems like it defeats the purpose of using sysbox in the first place)
b) I cannot use smbclient because I'd probably need to expose the domain passwords for some kind of user to the container
c) I've tried mounting the share to the Docker host and then sharing the mounted folder, only to discover that won't work either (note that sysbox has been declared as the default runtime):

docker run -v /mnt/storage:/storage --rm -it --entrypoint bash my_devops_image
docker: Error response from daemon: failed to create shim task: OCI runtime create failed: container_linux.go:425: starting container process caused: process_linux.go:607: container init caused: process_linux.go:578: handleReqOp caused: rootfs_init_linux.go:322: ID-map mount on storage caused: rootfs_init_linux.go:316: setting up ID-mapped mount on path /var/lib/sysbox/rootfs/660dc228a6a90bd401263902db0e1ff7da7a2cd106325d895d947bab97b6e9ff/top/merged/storage (likely means idmapped mounts are not supported on the filesystem at this path (unknown fs)) caused: Failed to set mount attr: invalid argument: unknown.

Googling this suggests that sysbox simply cannot handle such a volume. Are there any other options open to me?