Hi i'm just wondering why site collection administrator is hc webadmin and why i cant change that in creation?
 

Under the reseller when you will add the user it will consider be domain owner (Webadmin) , even if you create domain with New user option then HC ask for webadmin user name and password.
Once webadmin has been created reseller or host can't rename it in the control panel.

Yeah but my point was this.
 
1. Reseller has created webadmin. Webadmin account is in Webadmin OU in Active Directory.
2. Reseller has assingned  Exchange Plan to webadmin
3. Webadmin has created several Exchange users.
4. Now webadmin want's Sharepoint.
5. Reseller assigns Sharepoint plan to webadmin
6. Webadmin starts to create sharepoint site adn want's to put existing exchange user as site collection administrato. But that's not possible in site collection creation because hc panel puts webadmin as site collection admin. Webadmin dosen't know anything about sharepoint so should that person belong in site collection administrator group?
 
7. In creation process hc will create new account for sharepoint with following informations "Webadmin login name + 1" so windows pre 2000 logon information is DOMAIN\webadmin1 but user logon name with UPN suffix will be webadmin@domain.com.
But hey!! We have all ready user called DOMAIN\webadmin
 
/Jarmo

HC creates OU per domain bases so if a webadmin have 2 domains i.e
domain1.com
domain2.com
Then in active directory HC will creates 2 OU with domain name.
 
In your case if a webadmin have sharepoint site and mail domain name are same then your are correct HC will add SP and exchange accounts in a same OU.
 
There was also a suggestion to allow user to chose OU creation and name at the time of exchange domain creation. This suggestion already under development and will be included in next  HC8 installer.
Using new integration webadmin can chose unique OU as well as reseller will be able to share GAL segregation for two domains under different host (only reseller will allow to do that)