There is an AIX fileset bos.cifs_fs.rte which will allow you to mount a Windows share as an AIX filesystem, I'va played around with it some time ago, but never got it to work properly. Perhaps these days it is less buggy?
You might want to check it out. Just turns averything around: WIN becomes server, AIX is client.
If I remember right there are (were) some limitations, needs a 32bit AIX kernel for one. Was available in 52 - don't know if it is still around in 53.
HTH,
p5wizard