With Salesforce1, you can create an Opportunity, and you can Add Products to the Opportunity, but you can't select a PriceBook for the Opportunity. Until now. Provide the PriceBook Name in our custom picklist field and the active PriceBook will be set.
This package is offered as is. Feedback and comments are welcome, but functional requests will not be honored. You can bypass the entire package functionality by not providing a 'PriceBook to Use' field value on Opportunity create.