AeroLog Pro organizes custom fields differently from AeroLog For Windows. Therefore, you have to tell the Import from ALW wizard where your custom fields are in ALW, when where you want to put them in AeroLog Pro. The import wizard presents a page specifically for this purpose (shown below).

Using the mapping selector to the right, map each custom ALW field into the AeroLog Pro field of your choice. To map a field, click in the rectangle next to the AeroLog Pro custom field and use the drop-down list to select the ALW custom field, as illustrated below.

Repeat the process until you have mapped all of your ALW custom fields into fields in AeroLog Pro. Note that ALW "time" fields can only be mapped to AeroLog Pro "time" fields, "count" fields to "count", etc. It is okay to map the same ALW field to more than one AeroLog Pro field, or to leave a field mapping blank.