With the webservices, you can also create a sub category.
Here are the required parameters to create a sub category
user : Pseudo of a forum administrator
pwd : Password of a forum administrator
idforum : ID of the forum where the sub category should be created
idcat : ID of the category in which the sub category should be created
subcatname : Name of the sub category
subcaturlname : URL of the sub category, leave this empty to use the forum automatic function that generates URL.
homedisplay : Specifies if this sub category should be displayed on the forum homepage, 0 = hide, 1 = show.
hidelistofsubject : hidden on the topic list, 0 = show, 1 = hide.
subcatgroup : parameter which enables you to place the sub category in a sub category group, put here the sub category group ID.
Script example based on the sub category creation webservice
This webservice returns 3 parameters
subcatid : This ID of the sub category that has just been created
subcaturlname : the URL of the sub category
status : a message telling you if the sub category has effectively been created.