Some TA soldiers have been offered this in the past but if I was you I wouldnt be focussed too much on this route as there is no guarantee you will get the chance to transfer to Regs during an Op tour, especially with the SDR being released shortly.
There is a TA soldier out here with me now, Infantry cap badged and wanting to transfer to full time Inf. It has eventually come through for him during this tour, but he has had an absolute nightmare getting it. He started the process prior to deploying, and now that the RIP dates are looming close he has only just made any headway- That is with occasionally skipping the CoC, too, calling Glasgow directly.
It can be done, and most likely more easy if you are a member of the TA unit capbadged to that you wish to transfer to, but as The Iron says, I wouldn't bank your future on it- Anything can come up to block you.