The plugin is not compatible but works out of the box. But you need to translate the related products IDs by setting the _wcrp_related_ids to 'Translate'. The following steps will EliminatE the need to translate the _wcrp_related_ids field with Woocommerce custom related product Version 1.3.2.
1. Edit the /wp-content/plugins/woo-custom-related-products/woocommerce/single-product/related.php file with your code editor.
2. Move line 29 to line 21.
3. Replace line 22 with:
if ($related_products || get_post_meta($post->ID, '_wcrp_related_ids')) :
4. Add the following line after line number 44:
$related_product = apply_filters('wpml_object_id', $related_product, 'product', true);
5. Make sure that the field _wcrp_related_ids is set to 'Copy'.
6. Update the original product and its translation.
Now you should be able to see the correct and translated related products.
This workaround might not work anymore if you update the Woocommerce custom related product plugin. We will not support or maintain this workaround.