FNU as first name on H1B visa

[bazilasif]

HI

i don't have surname entry on my passport , i got a H1b visa stamped in london, they put FNU as my firstname on the visa, when i went to make SSN , they told that they will issue me the SSN with my first name as FNU,
i went to indian embassy and got a new passport with a surname entry on it, but still my H1b visa and the I94 contains my first name as FNU, i dont know what how to change it in my visa and immigration , does any body gone thru this type of problem , plz advise me what next i've to do after changing it on my passport, normally how long will it take to correct it on the visa


thanks

asif