H1-B visa stamp and new employer

[dewdrops232]

I am currently on H1-B status with a valid visa stamp until 18-Dec-2015 (through employer A). Through employer B, I have the H1B approval notice. I just started employment with employer C and they have filed my petition with the USCIS on 4/23/15 and do not have the receipt notice from USCIS, yet. I will have to travel to a European country to attend a conference (work-related, Jun 10) and would need a visa to enter that country. Since I do not have an I-797 notice of receipt from my current employer, can I still attend the visa interview (to visit the European country- must attend the interview within 15 calendar days of date of travel) with documents – H1-B visa stamp (employer A), the H1-B approval notice (Employer B) and the LCA or the H1-B petition documents (employer C) ? My company attorney is not very responsive about this, but I’m still pressing on this.
I’d appreciate your answer to the above.
Thanks!