Foreign names are written in katakana instead of hiragana. Some approximations have to be made for sounds that don't exist in Japanese. e.g. 'l' -> 'r'; 'v' -> 'b'. However there are some non-standard katakana extensions for non-japanese sounds like 'v'
Thus 'vu' can be written as ヴ and this can be extended to approximate other 'v' sounds such as 'va' which becomes ヴァ.
Furthermore, where several consonants are adjacent, it is not possible to express this exactly in japanese. You may need to add extra vowels (usually 'u') or otherwise approximate the sound.
So Belgenman Stovall => be ru ge ma n tso va ru => ベルゲマン ツォヴァル
This does of course assume I've got the pronunciation of your name right in the first place. You may need to adjust the above if it doesn't sound right.