How one can apply Hindi Matras(Vowels) on Roman letters? These Hindi Vowels work well on Roman letters on I-Phone by flipping Hindi and Roman keyboard. Is there any keyboard for this type of application?

For Example: open facility ??? ???????? o?pn f??c?lt? ..........How one can Merge these dotted circles with Roman letters?
This merging works on I-phone using Hindi/English keyboard. http://translate.google.com/#hi/en/open%20facility%0A%E0%A4%93%E0%A4%AA%E0%A4%A8%20%E0%A4%AB%E0%A5%88%E0%A4%B8%E0%A4%BF%E0%A4%B2%E0%A4%BF%E0%A4%9F%E0%A5%80%0Ao%E0%A5%8Bpn%20f%E0%A5%88%E0%A4%BFc%E0%A4%BFlt%E0%A5%80