Ok... I think this article clarifies things once and for
all:
http://www.understanding-islam.com/related/text.asp?type=question&qid=784&sscatid=523
Quoting from the article:
As should be obvious from the above explanation, any method or
sequence (of washing the body parts) that accomplishes thorough
washing of the body shall meet the requirements of the word
'igtesaal', and may, therefore, be adopted.
However, the Prophet (pbuh), whose actions, in carrying out the
directives of the Qur'an, provide us with the best example (the
uswah e hasanah) and the most desirable way of carrying out the
directives of the Qur'an would, generally, adopt the following
sequence in carrying out the Qur'anic directive of
'ightesaal':
1. Thoroughly wash and clean the private parts;
2. Perform wudhu/ablution (this would obviously help in
concentrating on thoroughly washing the parts that are included in
the directive of ablution and, thereby, hold a greater importance);
and
3.Thoroughly wash the rest of the body from head to toe.
So bottom line... the SOP for ghusl is basically following the
sunnah. As long as you wash up properly, then it's counted.