Only device inventory information (DCR) is migrated from LMS 4.2.2 and higher to PI 1.2. See the LMS 4.2.2 release notes here:
LMS 4.2.2 provides two export choices…DCR data and complete data. You can only import the DCR data into PI 1.2 using the device bulk import feature.
LMS 4.2.3 and PI 2.0 will support migrating a larger set of data, including the “complete data” export choice in LMS. PI 2.0 will provide a backend script for importing the data.
Is PI 2.0 available yet?
I want to migrate the complete data from LMS 4.2.3 into PI 1.2 howver you mentioned above that this is no possible within PI 1.2
PI 2.0 is currently targeted for Q2 CY13, most likely towards the end of June, and more migration mechansims will be in place for 2.0. Incase if you have a vaild SASU contact, you can migrate for free.