Issue type scheme Class is missing

Hi, we are developing a web-item in jira and through servlet we have created a form in order to create jira project from shared one.
The problem we have:

  1. Duplicated the project (but it has no configuration)
  2. Duplicated the original Worfkflow scheme
  3. Duplicated the original Issue type screen scheme
    But we miss the Issue type scheme in order to complete the duplication:

WorkflowSchemeManager workflowSchemeManager = ComponentAccessor.getWorkflowSchemeManager();
WorkflowScheme workflowScheme = workflowSchemeManager.getWorkflowSchemeObj( workflowSchemeId );


IssueTypeScreenSchemeManager issueTypeScreenSchemeManager = ComponentAccessor.getIssueTypeScreenSchemeManager();
IssueTypeScreenScheme issueTypeScreenScheme = issueTypeScreenSchemeManager.getIssueTypeScreenScheme( issueTypeScreenSchemeId );


IssueTypeSchemeManager issueTypeSchemeManager = ComponentAccessor.getIssueTypeSchemeManager();
IssueTypeScheme IS MISSING

the closest thing we did is get all single types:
Collection issueTypeSchemeId = issueTypeSchemeManager.getIssueTypesForProject( selectedProject );

So how can we retrieve the original Issue Type scheme?

Thanks