This article shows how to change view mode programmatically:

In RDPDFViewController class you can add this method:

- (void)setReaderViewMode:(int)mode
{
    int currentPage = [m_view vGetCurrentPage];
    if( m_view != nil )
    {
        [m_view vClose];
        [m_view removeFromSuperview];
        m_view = NULL;
    }    

    g_def_view = mode;    

    [[NSUserDefaults standardUserDefaults] setInteger:mode forKey:@"ViewMode"];
    [[NSUserDefaults standardUserDefaults] synchronize];

    CGRect rect = [[UIScreen mainScreen] bounds];    

    if (![self isPortrait] && rect.size.width < rect.size.height) {
        float height = rect.size.height;
        rect.size.height = rect.size.width;
        rect.size.width = height;
    }   

    if(SYS_VERSION>=7.0)
    {
        m_view = [[PDFView alloc] initWithFrame:CGRectMake(0, 0, rect.size.width, rect.size.height)];
    }
    else
    {
        m_view = [[PDFView alloc] initWithFrame:CGRectMake(0, 0, rect.size.width, rect.size.height-20-44)];
    }    

    [m_view vOpen :m_doc :(id)self];
    pagecount =[m_doc pageCount];    

    if (m_Thumbview) {
        [self.view insertSubview:m_view belowSubview:m_Thumbview];
    }    

    m_bSel = false;    
    [self PDFGoto:currentPage];
}