@thebitmuncher,
I have shared sample code with. This will help you to achieve your requirements. If there is still an issue than please share expected output in form of presentation so that we may further investigate to help you out.
Presentation pres = new Presentation();
String url = “http://www.google.com/”;
String text = “www.google.com”;
ISlide slide = pres.getSlides().get_Item(0);
IAutoShape shape = pres.getSlides().get_Item(0).getShapes().addAutoShape(ShapeType.Rectangle, 0, 0, 200, 250);
IPortionCollection portions = shape.getTextFrame().getParagraphs().get_Item(0).getPortions();
portions.clear();
portions.add(new Portion("Visit "));
IPortion portion = new Portion();
portions.add(portion);
portions.add(new Portion("."));
IHyperlink hyperlink = new Hyperlink(new Hyperlink(url), null, “”, false, false, false);
portion.setText(text);
portion.getPortionFormat().setHyperlinkClick(hyperlink);
pres.save(pptoutput, SaveFormat.Ppt)