seo friendly url issue using htaccess

[prithviphp]

I am having a problem with htaccess.

My non seo friendly url looks like this

 http://localhost/mybb/index.php?url=login/register

and the code is

 Options -MultiViews
 RewriteEngine On
 RewriteBase /mybb/
 RewriteCond %{REQUEST_FILENAME} !-d
 RewriteCond %{REQUEST_FILENAME} !-f
 RewriteCond %{REQUEST_FILENAME} !-l
 RewriteRule ^(.+)$ index.php?url=$1 [QSA,L]

And it returns

`http://localhost/mybb/login/register`

which is absolutely fine now I am trying to modify the url which will look like this

http://localhost/mybb/login/register/step/1

And the original url is

http://localhost/mybb/index.php?url=login/register&step=1

I tried with this

 RewriteRule ^(.+)$ index.php?url=$1&step=1$ [QSA,L]

it worked with the url which has step as param but if there is no 'step' in url then it doesn't work.Is it possible to add the /step/1 in the seo url only if the actual url contains the param called 'step'.Thanks.

[omoutop]

RewriteRule ^([^/]+)/step/([^/]+)/$ index.php?url=$1&step=$2 [NC,L]

This rule is close to what you look for BUT your two variables must have no / in them.
I cant offer more help, with the way your variables arr set (i mean with url='login/register', containing already a /)