It would take alot of work but it would be possible, it wouldnt really be instaled internaly so to speak but it would be inside of the cap. First you would have to take that silver cap off which is very hard its not threaded so you would need to put a rag around it (to prevent too many scratches) then you would have to put it in a vice and slowly twist and pull until it comes off. Then you would have to trim the filter to fit inside of the cap and once you get it trimmed its just a simple matter of gluing it in and putting the cap back on.
But be careful, only do this if your not too worried about getting some scratches on it... its almost impossible to avoid.