If you make changes in the Develop module in the LIghtroom 4 Beta and then choose to edit that image in Photoshop you will want Lightroom 4 Beta to render the PSD/TIFF file, not Photoshop. In order to do this, first choose Preferences > General and click the “Reset all warnings dialogs” button. Then, choose Photo > Edit In > Edit in Photoshop. A warning should appear: “This version of Lightroom may require the Photoshop Camera Raw plug-in version 7 for full compatibility”. Since LR 4 is in beta, this version of ACR is not available for Photoshop so choose the “Render using Lightroom” option. Now LR4 Beta will render the file and hand it off to Photoshop with all of the changes you have made in LR4 Beta.