Thank you for your forum post.
I assume TSM stands for Tivoli Storage Manager and not Taiwan Semiconductor Manufacturing.
SQL Backup has its own file format for the backup files it creates, therefore will only restore backup files created using SQL Backup.
The choice is yours, insist to your hosting company that they use SQL Backup to backup you source log shipping database or databases. Or switch to using TSM or native SQL Server backups files for your log shipping solution.