The three potentials for integration are always: existing pre-built integration; 3rd party tool; custom integration.
Asana doesn’t have an integration with Workflowmax, and it doesn’t appear that Workflowmax has one with Asana (looking at Workflowmax add-ons). So no luck here.
3rd party tool:
The main 3rd party tool for integrating with Asana is Zapier. Alas it seems Zapier does not support Workflowmax. There are other 3rd party tools for Asana integration as well, like Unito and tray.io, but I can’t see any support for Workflowmax among them - although you might want to reach out to them to verify that. But it looks like this option is a no-go as well.
You’re left with the option of building a custom integration using Asana’s API, if you have a developer resource available to you; or of hiring a developer to do it (best to contact @Bastien_Siebman if you’re interested in that).
This is probably not the answer you were hoping for, but this is what I see.
There is also importing/exporting to consider, but I don’t think that’s going to very viable in this instance. Perhaps others have an idea about this.