Do you mean with the SharePoint Workflow Integration processes?  If thats what you mean then, no you can use prebuilt custom forms, but you can mofify them after you design the process and K2 generates the forms.

Let me know if that answers your question

Hi chrisg,

 i meant the same sharepoint workflow process. how does this work "you can use prebuilt custom forms, but you can mofify them after you design the process and K2 generates the forms"? i am not able to understand this.

could you please give some more explanation.

 regards,

ritesh